Cause of death?

Hi.
So after 3+ years of abuse my m5n finally died. So I'm in the market, but before I settle on some model I want to figure out a cause of death. M5n was running hot most of the time, and my fan speed management policy definitely didn't help things (never overheated though, just hot), so I want to know if the death is related to that before I choose my next victim.

The symptom I have is: I press the power button, it lights up for a split second (and the power led as well), does a faint beep (not the normal beep though), and cuts the power, no other sounds from notebook (i.e. fan, hdd etc). Keep the power button pressed - it will blink/beep indefinitely on DC power.
I does the same thing even with hdd, cpu, memory and display disconnected. If it was not cutting power I would have thought about bad cpu.

Any thoughts on what actually happened?

P.S. anyone need parts for m5n?

 

I would guess that it has just finally overheated enough to have broken the motherboard. Over time, heating and cooling like that is bad. Keep in mind, that everything but the hard drive and screen would rather would at very very cold temperatures, so running them at close to 90C is bad for them.