X61 not quite dead

[karotlopj]

Following help here in getting an X61 working (to some extent) I thought I'd see if anyone had any advice about another one which I had given up for dead.

Yesterday I took out the battery and memory and plugged in the power supply. I got a beep sequence 1 3 3 1 which I now know is related to memory, so I put some in and the beeping stopped. When I connect the power a few leds blink and the fan starts up momentarily before stopping and switching off. No BIOS screen comes up.

The system got into this state when I tried to apply the Middleton BIOS update several years ago, and it never booted up since. Just wondered if anyone knew what went wrong and if there is a recovery.