Pc working normal after forced power up

[AaronM]

Hi guys. So I bought a used pc which was supposedly not working with the intention of fixing it. On initial power up the cpu fan and exhaust fan turned on but the exhaust fan shuts off after few seconds and theres no power indicators or post on the screen. The cpu fan just keeps on spinning though. So I took a thin piece of wire and grounded the green wire to the black wire on the psu just to force power in to see if it boots up or any diagnostic lights flash to assist me in diagnosing the fault. After inserting the wire I plugged in the power supply and it booted up and I had a post on the screen. I then removed the wire to see what happens and to my surprise the pc is working fine now. It's restarting, shutting down and working normal without the need of the signal wire on the psu having to be grounded. Could someone perhaps have an idea on what could've been the fault whereby a simple kick start solved it? Thanks