I have a quite old computer (ECS GeForce 6100PM - M2 V2.0).
I am running Windows 7 and before today I was having the issue described in the title, but I was able to boot into debugging mode. Not anymore.
The CPU is not overheating (44C), I cleaned all dust, which wasn't much. I ran memtest and did two passes with no errors. I unplugged everything (RAM sticks, Graphics Card) and the computer still won't get past the Windows logo before shutting down.
I tried Windows 7 USB, shuts down after "loading Windows files" message, so I can't even format and reinstall.
I tried booting from my Linux live USB, shuts down with every option except "run memtest".
Going into BIOS it will run indefinitely.
Here's a picture of the computer's insides, if it helps:
Video of the problem:
I'm all out of ideas, anybody?