Normally you can go to the Control Panel and click on Add/Remove Programs (in Windows XP), or Programs and Features (in Vista or Win7) to remove a program from the computer.
If you do this process, do you get an error message of any type? If so, please let us know what it says.
You can try booting into Safe Mode (press F8 when you start up the machine), and log in as Administrator. You should be able to uninstall the program at that point by going to Control Panel and using Add/Remove Programs or Programs and Features, depending on which Windows operating system you are using.