Recently build a Linux desktop using MSI motherboard and Core i3 (can't remember which model).

Worked fine for a bit.

One day refused to post. Fans came on though.

Next look at it, fans did not come on at all.

From what I can work out, PSU is shutting down almost instantly at power on. Eazy Debug LED flickers for a moment. Have a fan attached to Molex connector - it twitches but does not spin.

That's short circuit protection behaviour?