it will power on your motherboard with a RED led ligh and all the other devices connected to your mobo but they wont be detected as well since most of them are dependent on the CPU installed (such as PCIE). (i dont about old school motherboards about beeps and all that). it will just say that the CPU not detected message.and it wont damage anything as long as you put the power cables on the right pins. highly advise trying NOT to do whatever you are trying to do there tho. are you just rechecking if your other components are still working after a busted CPU?