You are probably infected with the Aurora trojan, a real stinker to remove. Your best bet is to download HijackThis, do a scan (do not delete anything yet!), then post the log in a new thread at the SpywareInfo Malware Removal forum. They have some crackerjack advisors who can walk you through the removal process.
It seems to have worked. They gave me two sets of suggestions: one having to do with the HijackThis info; the other was about spyware removal. I wasn’t able to do the HijackThis strategy but went ahead with the spyware removal. That by itself was enough.
If anyone is still reading this thread and interested, the solution seems to have been downloading an add-on to Ad-Aware - vx2cleaner. No problems for a couple of days now.