Computer powered down in stages

[memphis_1220]

The strangest thing happened a few minutes ago, in the following order.

1. Computer goes silent, fans turn off.
2. Fan controller display loses its backlight.
3. Computer switches off (no bang but very audible).

Initially I thought it was a powercut but everything else was still on. I turned my computer back on and was suddenly without any display. I then tried to turn off the computer but neither the power button (not even holding for 7 seconds) nor reset button worked. After using the power supply switch and switching to another power cable for my graphics card everything seems to be ok now.

I know it is a long shot, but does anyone have a clue as to what happened here? I was thinking it was my hsf that failed and subsequently shutdown but it is working, as with everything else in there that should be.

 

[engiNURD]

sounds like a psu issue.