I'm helping someone with their 2 year old computer that they said died during a lightning storm.

When you push the power button, absolutely nothing happens. I went ahead and advised them to buy a new power supply but that didn't help - still nothing.

I disconnected everything I could on the inside (memory, hard drive, disk drives, etc.), but nothing. The only thing that shows any life is a little green light on the motherboard that lights up when power is supplied.
So does this sound like the motherboard is fried? The light makes me think the power supply is working. Any ideas of other things I can check? Thanks.

Have you checked the cable that connects to the power button? Is it plugged in properly?

I would say this is because they did not have a surge protector on their computer which means that their computer has been fried. Basically the best thing to do would be to get a new computer or if you want to spend some money trying to fix it then start replacing things one by one in the following order and see if it works. power supply, motherboard, CPU, hard drive. Chances are though its going to be cheaper to buy a new prebuilt box then to replace all those things

If the board is not beeping, even after removing the RAM sticks, it's possible the board is fried. However, try resetting the CMOS by removint the battery for upto 3 hours...