If you think you're having problems with your PC, here are some things to try.
If your using Windows XP, make sure you are update to date with the latest patches and upgrades by using Windows Update.
A excellent FREE anti-virus program is AVAST!, which is currently what I use and have no problems at all.
A good spyware scanner (seperate from a anti-virus program) is Spy-bot, this includes a blocker in the program called "immunize"
Two other scanners for spyware that I use are Ad-Aware and the Yahoo!
toolbar, these scanners have to be run manually and do not block
spyware, but are excellent for finding it if you are infected already.
With all the security holes in IE, I prefer to use Firefox as my default web browser.
All of these programs are free and available at http://www.downloads.com