Problem--- Like a freeze but not exactly

Guys, first of all: The NG is outstanding! What a Cockpit, what a fusselage, well done! But I´ve got some serious problems with your beauty! The first time my problem occured was when I changed from the window mode to the full window mode. The second time , when I was standing on the Ground. I just left shortly to make some food but when I came back the problem occured again! The problem is: Whatever I press - nothing happens. Eg. the alt key---> No alt-bar! Futhermore, when i press space to look around, the normal cross dont occure, there is only the hand what u can see e.g. when you switch a switch! I can still change the view via the yoke! The only thing I can do is to leave the FSX via the task-manger? Anyone out there with the same problem or who can help me? Cheers!