Virus Tips

Computer viruses are small software programs that are designed to spread themselves from one computer to another and to interfere with computer operation.
A virus might corrupt or delete data on your computer, use your email programme to spread itself to other computers, or even erase everything on your hard disk.
Computer viruses are often spread by attachments in email messages or via instant messaging. That is why it is essential that you never open email attachments if you're even remotely unsure of their origin.
Viruses can be disguised as attachments of funny images, greeting cards, or audio and video files.
Computer viruses also spread through downloads on the Internet. They can be hidden in illicit software or other files or programmes you might download.
To help avoid computer viruses, it's essential that you keep your computer current with the latest updates and antivirus tools, stay informed about recent threats, run your computer as a standard user (not as administrator), and that you follow a few basic rules when you surf the Internet, download files, and open attachments.
Once a virus is on your computer, its type or the method it used to get there is not as important as removing it and preventing further infection.

Keep a regular backup of your important files (on a USB flash drive, writeable CD, tape, another hard disk, off-site etc.)
Be aware that most current viruses arrive as e-mail attachments and be very suspicious of any attachment that has any of the following file extensions:
.exe .vbs .scr .vbe .com .bat .shs .cpl .dll .ocx .pif .drv .lnk .bin .sys .eml .nws
(do not click on attachment files when names end with any of the above).

These dodgy attachments can arrive seemingly from someone you know (but without that person's knowledge), so attachments are not safe just because you know the sender. Note: reading the mail itself is safe, but clicking on any attachment can spread a virus instantly.
Ensure your anti-virus programme is up-to-date and operating correctly.
Update the virus definition files regulary, typically once a day but no less than once a week.
It is impossible for anti-virus programmes to protect against all new viruses, so your best protection is to always be cautious about opening e-mail attachments.

Viruses are usually written by students with too much time on their hands, but a few are very sophisticated and obviously written by professionals (disgruntled employees, frustrated programmers or just basic troublemakers and show-offs).
While there are untold known computer viruses, the number of truly original viruses is actually quite small; copy-cat viruses usually proliferate after any well-publicised virus incident.
For example, there are apparently several hundered variants of the "ILoveYou" virus; most are just plain copies or minor variations of the original.