windows 8 can't focus on task manager when a game hangs

this is a problem i have been having(win8pro, amd 4850, whql drivers) when/if a full screen game or 3d stuff hangs up, on windows 7 you can open the task manager (by any means, ctrlshift esc, or ctrl alt sup, or alt tab and right click task bar)and end the process, but on windows 8 the games keeps some kind of lock on the desktop and i can't kill the process because i can't get focus on the...