A program or a single file? If you're running an uninstaller, right click on it, and select 'run as administrator'. If it's a single file/folder, right click > properties. Select the security tab, then hit advanced. On the new windows that comes up, select 'change' next to 'owner', enter your username (should be the same as the folder name at "C:\users\<your user name>", and hit 'check names'. Then hit ok > ok > ok. You should now hopefully be able to delete it.