computer virus

  

A computer virus is a small software program that can spread from one computer system to another and cause interferences with computer operations. A computer virus has the capacity to corrupt or to delete data on your computer and it can use an e-mail program to spread the virus to other email addresses in your online address book. In the worst case scenario, it can even delete everything on your hard disk.

Forms of Computer Viruses

In the same way as viruses harm peoples' bodies, computer viruses can do considerable damage to computer systems. Viruses are infections. Computer infections can come in several forms and your computer can "catch" one in several ways:

• An email virus is one type of computer virus. An email virus can travel through attachments in email messages and can automatically replicate itself by mailing itself to dozens or even hundreds of people on your list of contacts found in your online address book. There are email viruses that can launch themselves into your computer while you are simply viewing the messasge. You don’t even need to double-click the message in order for the message to install itself.
• A Trojan horse is not a virus. It is a computer program that claims to be a game but, in actuality, will just do damage once you run it. It may even erase your hard disk. It cannot automatically replicate itself.
• A worm is a type of software called mallware that uses security holes and computer networks in order to replicate itself. The worm will scan the network for machines which carry a particular security hole. It will then copy itself to the machine through the security hole and will start replicating itself.

Viruses in general, start working and spreading once you start using the application or program to which the virus is attached. For instance, a program that has a virus in it will place the virus in the system’s memory each time that program is run.
Once the virus is in the memory, one of several things can happen. First, it can be programmed to attach itself to other programs and applications, folders, or disks. Second, if given the chance, it can infect a network.

How Computer Viruses Are Activated

Computer viruses are easily spread through the use of attachments in various email messages or via messages from instant messaging; so, you must never open unexpected email attachments unless you know and trust whoever sent the message.
Be very careful as computer viruses can be easily disguised as ordinary-looking attachments or even as attractive images, funny graphics, cards, video, and audio files. Computer viruses can also spread through downloads you do while online. They can be hidden in software, especially in pirated items, or in other programs and files which you are downloading.

How Computer Viruses Operate

Viruses operate in a multitude of ways. Some will stay active only when the application to which it is attached is running. Others will be inactive once the computer is turned off, while some will run every time you turn your computer on after it has infected the network or system files.
There are some indicators that will tell you that your computer is infected:

• Your computer is running slower than normal
• Computer applications are not working right
• Disk drivers and disks have become inaccessible
• You cannot print
• You find unusual, error messages
• Dialog boxes and menus are distorted
• You find double extensions on attachments which you’ve recently opened (ex. gif, jpg, vbs)
• Your antivirus program is suddenly disabled or cannot be restarted
• Antivirus programs cannot be installed in your computer or cannot run
• New and unusual icons suddenly appear on your desktop
• Strange music or sounds suddenly play from the speakers
• A program you typically use suddenly disappears from your computer without you purposely removing it

To safeguard your files and to protect your computer, take time to understand computer viruses and what you should avoid doing to save your system from the virus. Be sure to always turn on the firewall, keep your computer’s operating system updated, update your antivirus software, and use updated antispyware programs

Read more at http://www.yourdictionary.com/computer-virus#Fd0uOqOb57dUeigc.99

Read More

Computer Virus Information

What is a computer virus?

Think of a biological virus – the kind that makes you sick. It’s persistently nasty, keeps you from functioning normally and often requires something powerful to get rid of it. A computer virus is very similar. Designed to relentlessly replicate, computer viruses infect your programs and files, alter the way your computer operates or stop it from working altogether. It’s estimated that the Conficker virus infected more than 10 million computers in 2009. Tens of thousands of computer viruses now operate over the Internet, and new computer viruses are discovered every day.

How does a computer virus find me?

Even if you’re careful you can pick up computer viruses through normal Web activities like:

• Sharing music, files or photos with other users
• Visiting an infected Web site
• Opening spam email or an email attachment
• Downloading free games, toolbars, media players and other system utilities
• Installing mainstream software applications without fully reading license agreements

What does a computer virus do?

Some computer viruses are programmed to harm your computer by damaging programs, deleting files, or reformatting the hard drive. Others simply replicate themselves or flood a network with traffic, making it impossible to perform any internet activity. Even less harmful computer viruses can significantly disrupt your system’s performance, sapping computer memory and causing frequent computer crashes.

What are the symptoms of a computer virus?

Your computer may be infected if you recognize any of these malware symptoms:

• Slow computer performance
• Erratic computer behavior
• Unexplained data loss
• Frequent computer crashes

Computer Virus Help: Arming yourself with the best computer virus protection?

When you arm yourself with information and resources, you’re wiser about computer security threats and less vulnerable to threat tactics. Take these steps to safeguard your PC with the best computer virus protection:

Make sure that you have the best security software products installed on your computer:

• Use antivirus protection and a firewall
• Get antispyware software
• Always keep your antivirus protection and antispyware software up-to-date
• Update your operating system regularly
• Increase your browser security settings
• Avoid questionable Web sites
• Only download software from sites you trust. Carefully evaluate free software and file-sharing applications before downloading them.

Practice safe email protocol:

• Don't open messages from unknown senders
• Immediately delete messages you suspect to be spam

An unprotected computer is like an open door for computer viruses. Firewalls monitor Internet traffic in and out of your computer and hide your PC from online scammers looking for easy targets. Products like Webroot Internet Security Essentials and Webroot AntiVirus with Spy Sweeper provide complete protection from the two most dangerous threats on the Internet – spyware and computer viruses. They thwart threats before they can enter your PC, stand guard at every possible entrance of your computer and fend off any computer virus that tries to enter, even the most damaging and devious strains.
While free antivirus downloads are available, they just can't offer the computer virus help you need keep up with the continuous onslaught of new strains. Previously undetected forms of can often do the most damage, so it’s critical to have up-to-the-minute, guaranteed antivirus protection.

Read More

virus

In computers, a virus is a program or programming code that replicates by being copied or initiating its copying to another program, computer boot sector or document. Viruses can be transmitted as attachments to an e-mail note or in a downloaded file, or be present on a diskette or CD. The immediate source of the e-mail note, downloaded file, or diskette you've received is usually unaware that it contains a virus. Some viruses wreak their effect as soon as their code is executed; other viruses lie dormant until circumstances cause their code to be executed by the computer. Some viruses are benign or playful in intent and effect ("Happy Birthday, Ludwig!") and some can be quite harmful, erasing data or causing your hard disk to require reformatting. A virus that replicates itself by resending itself as an e-mail attachment or as part of a network message is known as a worm.
Generally, there are three main classes of viruses:


File infectors. Some file infector viruses attach themselves to program files, usually selected .COM or .EXE files. Some can infect any program for which execution is requested, including .SYS, .OVL, .PRG, and .MNU files. When the program is loaded, the virus is loaded as well. Other file infector viruses arrive as wholly-contained programs or scripts sent as an attachment to an e-mail note.
System or boot-record infectors. These viruses infect executable code found in certain system areas on a disk. They attach to the DOS boot sector on diskettes or the Master Boot Record on hard disks. A typical scenario (familiar to the author) is to receive a diskette from an innocent source that contains a boot disk virus. When your operating system is running, files on the diskette can be read without triggering the boot disk virus. However, if you leave the diskette in the drive, and then turn the computer off or reload the operating system, the computer will look first in your A drive, find the diskette with its boot disk virus, load it, and make it temporarily impossible to use your hard disk. (Allow several days for recovery.) This is why you should make sure you have a bootable floppy.
Macro viruses. These are among the most common viruses, and they tend to do the least damage. Macro viruses infect your Microsoft Word application and typically insert unwanted words or phrases.

Read More

How to get FREE HDTV (and all your DTV questions answered)

How you can get free HDTV with higher quality than available on your cable or satellite provider.
(Free after initial start-up costs, if you do not have an antenna already - generally, a complete setup can pay for itself in the cost of 2 months of cable or satellite)

First, I will dispell a few myths about digital TV, and then I will give you the basics on how to get things running.

First: I hear you need a whole new antenna set up to view digital tv.

Digital tv runs alongside analogue tv in the exact same spectrum. It uses the same channel frequencies, and the same antennas. (any antenna called HD antenna is marketing BS)
The only difference in broadcasting is the content of the signal and the decoding process.

Second: I need a whole new TV to view digital (and HD) tv.
Partially true, but not for every circumstance. You can use your same TV to view digital TV, but if it is an older TV is will not be capable of displaying the true quality of an HD signal, and it will require a converter box (roughly $50). This would be like a digital cable box, or a vcr that does the current analogue decoding for you.
If you own a new LCD/plasma TV, chances are it includes a digital tuner already (ATSC/DVB-t, depending on your location).
Check its specs before you go looking for a converter box.
(Note that some converter boxes are SD only, look for a converter box that outputs in HD if you have an HD ready tv)

Third: All DTV is HDTV.
These terms are commonly mixed up.
Digital TV is the same as the ordinary analogue broadcast television today, just in a different signal/processing format. (480i). Because of the superior nature of digital TV, you will get a perfect picture every time. (Or below a certain signal level, no picture at all. Much around the distance that analogue tv gets too fuzzy to watch)
HDtv is also purely digital (perfect picture every time), however it can go up to much higher resolutions, such as 1280x720 progressive (720p) or 1920x1080 interleaved (1080i).
1080i has roughly double the pixels of 720p, but half the framerate.
Also, just because a channel is broadcasting at an HD resolution, does not mean the picture is HD. For example, a show from the 90's cannot be broadcast in HD without remastering it, so it is probably standard definition (SD) stretched to fit the HD resolution. ("upconverted")

Fourth: Antenna TV? are you kidding me? Cable/satellite is far better! I haven't used an antenna for 20 years!
Cable and satellite used to be better than antenna simply because analogue broadcasts degraded quickly as distance increased from transmitters, and cable/sat companies could get optimum reception and send it to everyone.
With new digital broadcasting, you get perfect picture with as low as 20% signal (with a new tuner) - roughly about the same point when analogue broadcasts were too fuzzy to watch.
Cable and sat may have it beat in terms of offering quantity, but antenna tv now has them beat in quality. Generally the cable/sat companies will take the exact same broadcast stream and compress it to send over their network to you. The result? Decreased quality. With an antenna, you get the pure broadcast, exactly as it was intended to be viewed.

Fifth: My country is switching to dtv! Now I have to sign up for cable or satellite!

NO! This is exactly what the sable or satellite providers WANT you to think. You can continue to use your antenna (yes, even "rabbit ears") as long as you have the proper conversion box.

That's it for rumours/myths for now, on with how you can get your FREE tv (after initial set-up).

(If you have any more questions, ask them and I'll add to this.)

Step 1: Check your availability.

You can get FREE (after initial "build") high definition television in most areas. In fact, if you're within 120 miles of a tv station, chances are, you'll be able to get their channel.

The first thing you need to do, is consider your location:
What TV stations are around you, and broadcasting.
If you're in a semi-urban area, you're probably in an excellent area.
If you have very little around you, unfortunately, this will not work for you.
If you're in an area like Toronto or Buffalo, you can access two market's worth of channels, giving you 25 or more channels.

So, to begin our first step:
Visit http://www.2150.com/broadcast/default.asp and put in your latitude and longitude to see what TV stations are around you, and their approximate distance away.
If you don't know your latitude and longitude, visit this site:
http://www.gorissen.info/Pierre/maps/googleMapLocationv3.php
which will give the latitude and longitude of anywhere you click.
Just move around and zoom in to your location to get the most precise value.

Make a note of which stations are closest/you want to pick up, and what direction they are from your place. (Just general direction, for now.)

Step 2: Obtain an antenna and required materials

Despite what popular marketing wants you to think these days, ANY ANTENNA WILL WORK FOR DTV/HDTV BROADCAST RECEPTION. (Yes, even that 50 year old antenna you havent touched for 30 years!)
The only antennas which will not do much good are VHF-only, if digital broadcasts are mostly in the UHF spectrum for your area (Channel number above 13 from the broadcast search in the previous step means it is in the UHF band).

Some popular (good reception) antennas are below:
The Channel Master 4221, Channel Master 4228, and an example of an antenna you may very well have already on your house and you never use.

To go with the antenna you will need coax cable to reach your tv, a grounding block, and depending on your area, an amplifier.

A key part of low cost investment is having an appropriate tuner.
Almost all HDTV's (LCD/plasma) ship with a built in digital tuner. (ATSC for North America and a select few countries, DVB-t for the majority of the rest of the world).
If you do not (i.e. you have an old CRT tv or a new tv, but it doesnt have ATSC/DVB-t), no problem: you can get converter boxes for about $50 for a CRT tube, or many dvd recorders/DVR's are including ATSC or DVB-t tuners if you wish to go that route.
Note that a converter box which does not have HDMI/component will most likelt not output in HD, but downconvert the picture.

Another option is a PC-tuner, which can be as low as $40 these days.

Alternatively, you can build your own antenna which performs just as good as the commercial ones, if not better!
Check out the Gray-Hoverman antenna:
http://www.digitalhome.ca/ota/superantenna/
It's designed to be free and "open-source" welcoming people to make their own tweaks and get the best antenna possible. You can find the official plans at the site above, or you can read the antenna development forums at Digital Home Canada to see what changes people have made and what's the best type for you to make.

Step 3: Hook everything up.

 

 

Once you have your antenna, mount it where you will get best reception - The higher the better. If you already have an old antenna, leave it where it is and you can test how well it works later on. (skip to the next step)

I wont go into details for mounting antennas here, but there are three main methods:
Tower: freestanding tower holds up the antenna, sometimes attached to house for more stability.
Tripod - a tripod holds a mast, attached to the roof
Chimney - A mast is strapped to a (brick) chimney

There are also other ways you can mount an antenna, such as wall-mount (like I did, picture below).

Once the antenna is in place, you want to run your cable from the antenna to your TV, inserting a grounding block before it reaches the tv (to prevent problems from static electricity or lightning.
You will also want to ground the antenna/tower itself, according to local municipality standards to prevent damage to your home in the event of a lightning strike. 

Step 4: Tweak your reception.

Depending on the positioning of your antenna, you will find some stations are not quite at their best until you tweak the position for best reception of all stations.

If you desire, or the layout of stations requires, you can include a rotor, which rotates the pole holding the antenna to pick up various stations.

You can do this systematically (aka move it a little bit and see what happens) or you can do it precisely, using online measurements and values and a compass.
I found it easier to just do trial and error until it was perfect.
(A compass to put you in the general direction wouldn't hurt, however.)

If you are in a low reception area (usually because of distance) an amplifier will help.
There are two types:
a pre-amplifier ("preamp") - this connects as close to the antenna as possible, providing amplification on the cleanest signal it can. This is generally the best option, but often quite expensive.
The other type is a distribution amp, commonly used for cable systems - you plug it in somewhere along the line and amplify before you split.

Splitting the signal is possible, but you will need a tuner at each end, and signal will be reduced to both.
It is best to get one line up and running and see how things go before splitting. You may need to amplify to get even one line running. 

Step 5: Enjoy your new subscription free TV!

 

Sit back and watch your new digital TV.
It may only be a few channels for some people, but if you're in an area like me, you can enjoy 25+ channels, 20 of them in high definition.

The best part of it all? Once it's set up, there is NO monthly fee.
And hey, the superior picture doesn't hurt either.Enjoy, and I'll be happy to answer any questions in the comments. 

Read More