Good tip. Try this, AVG free, & spybot. I use those three on my work Laptop & i have no issues.
My exact same setup, though I've used Ad-Aware also, at times.
Sometimes AVG will show false positives, but ALL anti-virus programs do. Grisoft (makers of AVG) also have a forums section, which are up-to-date. Its a widely used program and fixes come fast.
My computers haven't ever been infected with a virus, since I started using it... and that includes the desktop, which is primarily used by my kids (and they'll click on most anything).