This type of applications does more harm than good. The software appears to be a big scam that does nothing and informs your about "problems" in your PC that actually don't exist.
I recommend booting in Safe Mode, but download a copy of Revo as well. To boot in Safe Mode, reboot the PC and then continuously press F8 until the service menu appears. Choose Safe Mode and install Revo, then get rid of WinSweeper. Reboot your PC again and that's it. The software shouldn't run anymore.
Additionally, while you are in the Safe Mode, go to Start > Run > msconfig, then switch to the Startup tab. Uncheck WinSweeper and reboot the PC.