after removing Spyware/Adware with it, caused the system to become unstable and blue screen on me a lot. Fixed it by reinstalling the OS. This was not recent, but was a year or two ago. Ever since I switched to Spybot instead and have not had any problems yet, knock on wood. :)
"Lady I only speak two languages, English and Bad English!" - Corbin Dallas "The Fifth Element"
Chances are you uncovered an existing instability. I've installed Ad-Aware on lots of machines without any problems at all. Windows is like a pit bull - feed it often and pet it occasionally, and it won't bite you.
They always believe that they are in control of their pet.
Cheers, Ben
"good ideas and bad code build communities, the other three combinations do not" - [link|http://archives.real-time.com/pipermail/cocoon-devel/2000-October/003023.html|Stefano Mazzocchi]