First, go in the ksp folder, and just copy the 'saves' folder to somewhere else. Anywhere really, desktop would work fine. That is to backup your saves. Second, you should tell us what operating system you are on. Lastly, yes, an uninstall/reinstall would work for sure. If you do that, don't forget to copy back your 'saves' folder into the ksp main folder in order to restore your saves. Cheers! P.S: I use steam so I can't give you any advice regarding the launcher/patcher. But reinstalling is will fix it for sure.