Check information in this review article: http://zardozz.com/zz/2010/11/a-perfect-software-uninst...
or visit http:uninstallmysoftware.com that also has uninstaller software and info on how to uninstall difficult programs.
You will need to use a dedicated software uninstaller utility.
There are a number of good ones listed in the review above and there are other sites listed there to link to for additional help.
Most complex software will require special removal because of the way it writes keys into the PC registry.
First remove it with a good software removal tool like those listed in the article above.
Then make sure the registry is cleaned up.
You can also find the top rated removal and registry tool software all listed together at http://rockbridgedownloads.com
including Spyware Doctor,
Regcure and others.
That way you can choose the ones you like the best.