Computer Wont Stay Off And Bios Update Failing To Launch?

Hi, if all hardware faults are eventually ruled out by taking all the good advice offered so far, and the system still restarts, to me that then sounds like something amiss in Windows itself.

It appears to be behaving as if the restart has been clicked rather than normal shutdown. Windows itself starts the shutdown of itself first with the last thing it does is to send the signal to the BIOS to finalise either the shut down or the restart.

Those signals come from Windows, the BIOS only follows the instructions.
It is maybe perhaps time to think of a fresh install of Windows to see if that cures the problem.

Just an oddball though from me, but you never know, it may be all that is needed before the computer starts getting much use and large amounts of data stored, which of course will mean having to make a backup.

Nev.