Launch button on League launcher not working + can't accept Terms of Service.

Regardless if I run it as admin or not, the League launcher is incredibly laggy/frozen/nonresponsive. Clicking the Launch button will make it grey out and play the sound, but it'll become orange and clickable again. Nothing happens after this. Occasionally the first part of the Terms of Service will pop up to accept/reject, but accepting it does nothing.

I've tried installing Adobe AIR, deleting the LoLLauncher folder, and deleting the LolAirClient folder in Riot Games>League of Legends>RADS>Projects, although this hasn't helping. I have all of my antivirus programs disabled.

EDIT: Uninstalled the game, currently trying to reinstall. It seems to have reinstalled correctly, but I'm still having the same issues.

Using the repair button in the Launcher does nothing whatsoever. I'm using Windows 7.