One tip I learned after my Abit RAID mobo died:

Look at the capacitors on your motherboard, make SURE they have FLAT tops. If they have raised tops, the mobo died and you'll have to replace it or replace the capacitors.

I NEVER thought of that until my dad looked at my mobo and was like, "Hey, these capacitors burst, no wonder the thing isn't working!"

We thought it was the hard drive, but it was the capacitors. (I am now using the hard drive in this comp, a nice 40GB).

There were batches of defective capacitors which ended in the market, a lot of them in motherboards.

Motherboards with this bad capacitoes can work for a while, can die very soon or just keep working for a long long time. Sometimes the dead capacitor is not so 'essential' that the mobo wont work without it.

Anyways, your suggestion is okay, as a lot of people don't look this details when the can't find the source of the problem.