I recently purchased a 7D. I had been using it with my 580EXII with no problems. Today I went to use the pop up for just a touch of fill flash and it would not open when I pressed the little button on the side. I even tried switching to fully auto mode (green box) and it would not open. I then went in to the menu and it will not let me into the built in flash menu. It says "menu can not be displayed. External flash is attached." I have checked the contacts, i have tried reseting all the settings, I have tried pulling the batteries. Any thoughts?