Macbook Pro - startup issues

I have a 15'' MacBook Pro, aluminum (early 2008), and my startup issues are the following: after closing the lid a few days ago the Macbook was in a shutdown state. The battery is fully charged and the computer pluged in, attempting to startup has significant problems. There is no chime, and no screen, everything stays black. The status LED is unlight. When the I/O is pressed, the computer breifly attempts waking up, then clicks off. When held down, the computer begin's it's startup process, the fans start whirring, the optical drive powers up, and the status LED flickers, then before anything can happen the whole unit powers down.
I've tried resetting the SMC, PRAM (which is not possible because the computer does not have a chance to recognize startup commands, the same is true of holding click to release a CD, or firewire mode, or anything else, I've tried them all). I tried reseating the RAM, which did no good, except that without any RAM the computer still delivers an error message indicating such, which tells me at least that the firmware is not dead. My next step was to reseat the HD and optical, which I also did to no avail. I've exhausted all the options I know of, except take it to Apple and pay the $310 or whatever it is. I don't know if it could be because of the whole NVIDIA card recall thing, but unless I can find another solution, I'm gonna see if I can go to Apple and play that card hoping for a logic board replacement. If anyone has had a similar problem or knows what my problem is, help would be greatly appreciated.

I reckon something to do with the power delivery on the motherboard is the issue. You havent spilled anything on the laptop have you?

Wouldnt harm it to try a known working battery if you have one - but I dont think thats the issue here.