Make sure you have all the latest updates, and if you’re using Vista, then upgrade to XP as it is far superior to Vista. (Vista really is a totally crap OS)
If you’re using Firefox, make sure you have your anti spyware up to date, as mine has to work overtime to keep out all the crap that Firefox try’s to let in. (Hardly needs to do any work at all with IE)
Aren’t computers wonderful?

Bill