This seems to be a fairly common Vista problem which seems to have started following a fairly recent update. I have a similar problem ans so do quite a few others in this forum. No one seems to have an answerb but there is a Vista SP1 update out in about 2 weeks time which I am hoping will solve the problem. I'm sorry I can't really help you.
Use anther spyware detector suc as Ad-Aware 2007