controll panel add/remove programs go to it and click remove
and if that doesn't work, go into C:\program files and find the folder, delete it, and empty your recycle bin. And THAT doesn't work, then google "AVG free," download it, and then use that to get rid of it. And if even that fails, then God help you. You're screwed.
it can reinstall itself, SCAN your computer
Have you got an anti virus program? If so, run a scan.
If you don't have one.. you can try and download a free anti virus program like:
Avast AVG
you can also try this online scanner by Microsoft:
http://onecare.live.com/site/en-gb/default.htm
http://www.wiki-security.com/wiki/Parasite/Antivirus2008