Reading a post on Dave Winer blog I caught the following snippet

NY Times survey of spyware and adware. "...a program that creeps onto a computer’s hard drive unannounced, is wrecking the Internet." 

I've noticed that every time I sit at the computer of a non-technical Windows user I end up spending at least an hour removing spyware from their computer. Yesterday, I encountered a particularly nasty piece of work that detected when the system was being scanned by Ad-Aware and forced a system reboot. I'd never realized how inadequate the functionality of the Add or Remove Programs dialog was for removing applications from your computer until spyware came around. After I was done yesterday, I began to suspect that some of the spyware that was polite enough to add an entry in "Add or Remove Programs" simply took the Uninstall instruction as a command to go into stealth mode. One application made you fill out a questionairre before it let you uninstall it. I wondered if it would refuse to uninstall if it didn't like my answers to its questions.

Something definitely has to be done about this crap. In the meantime I suggest using at least two anti-spyware applications if attempting to clean a system. I've already mentioned Ad-Aware, my other recommendation is Spybot - Search & Destroy.