I tried downloading a file last night and it ended up being called setup 903. I opened the program and it disapeered from the file and now i have a “look-a-like” mcafe warning your computer is infected poping up in my start bar. It says “You have a security problem!” and i know its fake. When i have clicked on it it sends me to this site and tries downloading fake spyware onto my computer

http://live-antivirus-scan.com/2009/1/en/_freescan.php?nu=77100108

I downloaded Hijackthis and AVG but neither has worked.

Can anyone help?