Consider using an alternate browser- such as Mozilla Firefox, Opera Web Browser, Apple Safari, or Google Chrome. Internet Explorer is very popular, and therefore a large target for those who create viruses.
If you would rather use Internet Explorer, make sure you use the most up-to-date stable version, currently Version 8. Make sure to turn on the anti-phishing option on the Set-up page.
Find your browser's option to turn off pop-ups. On your Internet menu bar, go to Tools, then Internet Options. For Firefox, install the Ad Block Plus extension.
Learn to recognize what is an advertisement on the Internet, and what is a pop-up from Windows or your anti-virus software.
Clear out your temporary files and cookies often. On your Internet menu bar, go to Tools, then Internet Options.
Keep your antivirus software up-to-date.
Consider not using Norton or McAfee. Much like Internet Explorer, they are popular, and thus, large targets. Some viruses are written specifically to get past anti-virus products. They also are notorious for being resource hogs. We recommend using Trend Micro Internet Security.
Run full system scans of your computer. Do this as often as you find necessary, at least once a month or so.
There are certain programs and websites that you need to be extra careful when using.
Beware of social networking sites, such as MySpace.
Beware of file sharing software, such as LimeWire.
Beware of torrents.
Beware of the “shady” side of the Internet. A thumbnail of an enticing picture is often nothing more than a link to a virus.
Be careful opening emails, especially from people you don't know.
Never open an attachment unless you know what it is.
As soon as you see signs of infection, disconnect your computer from the Internet (unplug your network cable). Many viruses will open up back-doors to let other infections in, and it will continue to get worse. Also, many viruses will use your computer as a “zombie,” and you may unknowingly help to infect other people's computers through the Internet and email.
Using these tips and some common sense will help to reduce your odds of getting a computer virus. However, there is no way to prevent 100% of viruses.