My computer used to have this problem. You can see if there is anything wrong with ALT. 90% of the problems are caused by this key. Press ALT more, and it will be almost ready in a few days. Adventure Island window and full-screen conversion are both ALT+ENTER keys, so you can see that there is something wrong with your ALT key. Really can't. Go and fix it. I hope it's adopted. It's the first time to say so many words