Only way I know of doing this, is, to add chip/fan, memory, and graphics card attached to monitor and boot to bios. Someone else may have another solution and I will learn something new also.
I keep a set up like this on desk to test PC hardware etc when I have them in for repair or testing.
I have a PC attached through a switch box for Monitor keyboard and mouse to the test rig. When I need to test anything just turn the switch box to rig and just pop it into the rig and use the monitor keyboard and mouse of the PC thats attached to the switch box.
This way I can test Hard drives graphic cards sound etc without any hassle.