spyware, malware, popups

I have done all I can to remove my IE hijack. Randomly while working on other projects, my IE will open and pop up and ask me to download a progrma to clean my PC. I have used all the programs I can think of.. hijackthis, search and destroy, AVG antispyware, and my antiviris of course. I even used trend-micro's online scanner. Still, popus and hijacking and autodownloading of programs I dont want.

Any advice on where to look on my PC to kill this/these thing(s)?

avssytemcare.com is one of the pop-ups (googles it, cant find much to help)
SytemErrorFixer is another one.

Pain in the buttocks, man

Any help would be rewarded with a SMILE and a thank ya!