So I had my xbox 360 plugged into a VGA box that was also connected to my computer so they shared an LCD monitor in my room & everything worked then, I unplugged the xbox awhile back & I recently tried to reconnect it to the VGA box but now it says 'Out Of Signal Check Video Cable' & when I switch it to the PC it's just a black screen but when I connect it in our up stairs room it works again. I can't figure this one out.. Could it be the plug in the wall or something?