In order to unintall this software, you can try using the standard way. Go to Start -> Control Panel -> Add/Remove Programs (Windows XP) or Programs and Features (Windows 7), select the program and hit Uninstall.
If this doesn't work, you can use a third-party software. Revo Uninstaller is an utility specially designed for this kind of operations. This tool will force any application to uninstall and remove its traces from your PC.