I am trying to get Garrys Mod working. I have it on Steam. It'll launch, but then it will continue loading with the little 'loading' thing in the bottom right corner of the screen (like HL2). I want to try clicking on 'verify integrity of game cache' but when I do, it says I must close all tools or games running. As far as I can tell, no games or tools are running. How do I fix this? or are there any more fixes for gmod?