Cannot click, type, or interact with anything at the start of a game.

Alright, I've been having a pretty persistent problem as of late. Whenever I start a a game, I cannot interact with anything in-game. I can move my screen, but i cannot click or type. The only thing i can do is Alt+F4. However, this doesn't happen all the time. Some games it doesn't happen, sometimes it resolves itself after disconnecting and reconnecting, and other times, i can't do anything to fix it. I've tried all of the standard fixes like not Alt+Tabbing when the game is loading, restarting my computer, and using the repair options in the League of Legends client. Is there anyone who has this problem or knows any fixes? Any feed-back would be greatly appreciated.

Thanks.