when you installed Screenshot Captor, the installer created a ProgramGroup in your Startmenu. There you can find a "Uninstall Screenshot Captor" entry which will uninstall the program for you.
Normally the installer also creates, as any other well programmed application under Windows do, an entry for uninstalling Screenshot Captor in the ControlPanel->Software Tool. I can't understand what happened when you don't have such an entry. Strange!
If you don't mind to tell us, what you don't like in ScreenshotCaptor, i think we and mouser will appreciate your hints. This will help mouser to improve his program. Would be very kind of you.