Can someone help me ? I bought a working 2yr old Apple Cinema Display A1038. I hooked it up to my 6yr old G4 M7891LL/A. When I turned on the G4 the monitor showed a gray screen with Apple logo. Then a spinning dash icon. 30 sec. later the screen goes black. I can not use the mouse. I have to turn power off to shut down. G4 has what came standard with it. Other than extra memory installed 2yrs ago it is stock. Thanks.