ok, so none of these work. I have an HP ProDesk 400 G5 and there is little to turn on or off (none actually) in the bios. If I swap monitors and cables with another G5, the problem stays with the PC. It does ‘see’ there is a monitor as it tries to use it and not the VGA out… until unplugged. So, I think it it is the system board and was hoping to find the % of these going out.