Won't start up when I boot up.

I have a PB 864 MHz 12". Currently, the machine is not booting up. I have taken the battery out and pressed on the power button for about 5 seconds, put back the battery and it would start up after a couple of tries. Now however, when I try to start it up now, I hear a kind of click when I press the power button. However, I don't hear the bong. I hear the hard drive spinning but nothing on the screen.

When I plug the adapter into the computer, the green thing on the adapter lights up. When I did get it to boot, the thing stayed on all day as long as I didn't shut it down.

Any suggestions? Thanks in advance.

Well, I am honored for the award. However, I have to report that after successfully doing the DC to DC board repair, I have not used the computer for a couple of days. Now, I try to start it and it is doing the same thing. However, after doing the repair, it was working. I used the computer after that for a couple of days and it booted each time.

It seems that now when I leave it unplugged and not booted for a couple of days, it went back to this problem. By the way, I didn't get that download that you recommended Mayer. If I get it to work today, I'll download it. However, now what?