Hi
I have a dell optiplex 7060 Small Form Factor that I just got for free.

It turns on automatically the moment i plug it into the power socket, and turns off again after 15-ish seconds, then loops.
Unable to access bios/boot
Did work for a short while, managed to boot, after i most likely unplugged/replugged CPU pin, but doesn't work anymore.

-changed cmos battery
-cleaned components
-unplugged and re-plugged everything
-tried different RAM,storage,CPU and GPU. only thing i haven't checked is MoBo or PSU, reckon the PSU works, but there is no self-test button.

Any help would be appreciated