Effectively remove any security application
The free AppRemover utility enables thorough uninstallation of security software like antivirus and antispyware applications from your computer.
http://www.appremover.com/
http://download.cnet.com/AppRemover/3000-2096_4-10909880.html
I can't say personally how well this works -- a Big reason I use McAfee is that they have their own complete removal tool -- but it does have good ratings. Why bother? Malware often tries to disable anti-malware, so security software by design sends roots deep into Windows to make that more difficult. When you try to change security software brands or perform a major version update a simple uninstall often is not enough -- installation may fail or your new software [&/or Windows] may not behave/perform correctly. I've had enough problems with this in the past that their removal tool really is one of the main reasons I started running McAfee a few years ago [at the time I didn't know about this tool, if it was even available then].
