Motherboard problem. Is it toasted?

Factual Questions
1

The motherboard is an Asus P5L-MX.

The computer would give a BIOS Checksum error during POST but would otherwise boot into Windows XP. However keyboard and mouse wouldn’t work and it was impossible to get into BIOS.

Then out of the blue the computer and the PSU wouldn’t start at all. Only the LED on the motherboard would light up, otherwise the computer was completely unresponsive.

So far I’ve done these:

  1. Checked PSU with a dummy load and is OK.
  2. Tried with another PSU and the computer wouldn’t start either
  3. Cleared CMOS and checked battery
  4. Removed everything from motherboard except CPU, CPU fan and the two main PSU cables
  5. Swiched the CPU and CPU fan with another similar model from my parts bin

Nothing of the above had an effect. Now, whenever I connect the PSU power cable the green mobo LED starts flashing and I hear a faint clicking noise from the PSU in sync with the flashing.

There’s no visible damage on the board (scorch marks, blown caps) or bent pins on the socket

Is there anything else I can do or is this mobo dead?

2

Could the case or power switch be a factor? Other than that I think you’ve covered everything I can think of. Bad motherboards are rare but they do happen.

3

This article might help.

If you clear the CMOS, be sure to unplug the computer first and plug it back in LAST.

Many times people THINK they’ve cleared the CMOS but they haven’t. You have to follow the correct procedure to be sure you’ve done it correctly. From one of my first posts here.