I FIXED IT EVERYTHNGS GOOD!!!!!!
I'd be glad if someone could help me. - BRAND NEW DELL INSPIRON N7110 - WIN 7 HOME PREMIUM Everytime the UAC window pops up, all program windows (e.g. firefox, ie, windows explorer etc.) aren't maximized no more. There's always a little space left above the program window and you can see the desktop. However Fullscreen videos and etc. work fine. Before a UAC message popup the window of programs fits to the screen as usual.  Thanks in advance for any helpful replies and solutions.
Windows 7 Display