[NOOB Q]: Motherboard does not respond to power button

Hey there, first time I'm posting here. Looking to be guided in the right direction, perhaps more than the actual answer (the amount of things one might try to google makes the task daunting.)

I have an old desktop computer that I built some years ago. It stopped working quite suddenly, and I have only now had the time to look into it again. However, there seems to be no life whatsoever, either by pressing the power button or shorting the power pins on the board.

The power supply was fairly new (replaced the original) at the time of malfunction, and it seems to work, since the green LED on the motherboard lights up. The speakers pop when I plug the cable in to the wall socket.

The motherboard is an Intel DP35DP. I don't any beeping at the time it stopped working, and there is no beeping sound now, although I have not yet run through a thorough test. There is absolutely no response to pressing the power button: no fans running, no harddrives spinning up, nothing at all.

Does it sound like I should chuck the motherboard and just move on?

BTW, I have connected both MB power as well as CPU power. CPU fan i also connected.

Sorry if I'm not being very precise. Hope someone can move me in the right direction.

p.