I have a 20" imac and it is missing the port for the dual display. it looks like some one pulled the port out of the mother board with needle noise pliers. now the machine thinks that a monitor is plugged in and messes up the resolution of the screen. I can change it back but every few minutes it sets itself back to the low res display. auto detect is off. is their a way to turn off that port forever? or any other ideas? 