I Can't Connect In General.

So every time I click on League Of Legends Icon, this error pops up almost immediately saying that "League is either not designed to run on windows or it contains an error." So I uninstalled league then re-installed it and it's still not working and I don't know what to do. I was waiting for these new star guardian skins, but now i guess I can't even purchase those if my client won't even open. Rip $50 riot.