All about viruses
When it comes to viruses we're not experts, but we know a man who is!
Probably the biggest force in virus detection is Sophos and their website is a first rate reference on the subject. Sadly, it's not available to private users. A version of the Sophos engine is now bundled with Webroot Spy Sweeper but we cannot recommend it; but we do recommend the Webroot Spy Sweeper (see What's malware?).
If you're looking for a virus detector then a search of the internet will produce many offerings and one of the best, AVG Anti-Virus is completely free of charge; but you must keep it and Windows up to date.
Many new computers come bundled with Norton Security Suite which (appears) to work fine until it's time to renew the subscription when suddenly things stop working and the computer grinds to a crawl. If your computer arrived with Norton installed we recommend that you go to Start/ControlPanel/AddRemovePrograms and uninstall it by clicking on the Remove button.
You can read more about this topic and others on our blog.