[CRASH] Can't click on anything in game

Everything in the client works great, the game starts loading. However my mouse never turns into the hand cursor. Once the game completely loads; none of my clicks seems to be registering actually within game. I can't press esc, nothing. I just bought a new monitor and started playing on a dual screen set up. Could this be the problem?

I just want to highlight this b/c there were many inquiries into this very problem several years back and I've only found the solution in only one of these many threads hidden away.

[SOLVED] Run League as Administrator.