Monitor clicks off when changing to games...

Ok so i've had a viewsonic a72f Perfect flat monitor for a long time now and i cant remember if its always done this or not, but more recently its been causing problems and overall annoying me. What happens is when i switch to a game and it switches to the point where the game should be in full control and graphics should be displayed it clicks and goes to a black screen. now the game runs fine when i click my mouse a few times. This also occured at some point when i used to play world of warcraft, i would literally have to hit launch then click my mouse like a mad man otherwise the game would be minimized and i'd be back to desktop.
Now when im running futuremark's 3dmark when it switches from loading screen to the game test it wont test, saying the window lost focus. I can't seem to figure out why my games etc... are always losing focus. It is really annoying though and i have a feeling its causing some crashes but im not sure. I've installed tonnes of drivers for both my vid card and monitor and it wont stop doing it. Does anyone have any idea of how to fix this other then buying a new monitor?