Speaking of Crippleware, some of those "Registry Cleaners" are terrible. They look slick, but if you install the "trial" version, they keep popping up a scanner periodically that comes up with a bunch of inconsequential Registry problems, but when you click the "fix" button, it directs you to their web site to buy the full version that supposedly actually fixes the problems.

There's also an infamous virus scanner floating around that installed itself as an IE "Browser Helper" which then downloads an exe that causes IE to continuously pop up virus warnings, then automatically redirects you to their site where they sell the program to get rid of it.

There is no way to get out of the loop, because everytime you browse to another web site, it will carry you back to their web site. I'm not sure where I caught it from, but it appeared on my PC one day and drove me crazy.

Even Norton didn't clean that one, because a hidden exe and all the registry settings were self-mutating and had random names, and that exe created yet another exe that did the dirty work - so even if Norton deleted the obvious one, it kept coming back. But after some Googling, I found someone who had figured it out and published the solution in his blog. It didn't find the self-mutating file either, but just disabled all the ways that it could be re-started.

Last I heard, there were lawsuits out the wazoo trying to go after that company, but seems like they were offshore. They're probably still out there somewhere.