Start, [Settings], Control Panel, Add or Remove Programs. Anything else (like CCleaner) risks messing up your system royally. If you have something you can’t uninstall cleanly, it’s best to learn something about Windows administration and take out the garbage piecemeal. One place to start is the registry. Look under the branch
HKLM\SOFTWARE\Microsoft\Windows\Uninstall.
Step through that gaggle of hex strings one by one in search of your offending application, and remove any entries named NoModify or NoRepair. That should make the program show up in the list of things you can uninstall through Add/Remove programs. If all else fails, delete the entire key before proceeding with a manual unistall. That involves manually removing any folders and shortcuts created for the application, as well as any stuff in the user data folders.
Um, @simonmenke , I think the OP was pretty explicit about the OS in question. As always, if Mac is the answer, you don’t know what the question was.