Q: Macbook 3.1 will not power on

I have an interesting problem. My Macbook (pre-Unibody model) will not power on. For a while, it did power on but the fan ran continually at maximum RPM and the battery didn't charge. Additionally, the battery wasn't detected by OS X at all. Now, I plug the Macbook in, and the indicator light turns green. Press power button - nothing. Unplug power cable and try to boot off the battery (as it still has some charge) - nothing. I tried a SMC reset, didn't do anything as well. I'm at a loss as to what I can do, and I know that if I take it to Apple they'll instantly suspect the logic board and want me to fork over a good amount of cash. Does anyone on here have any ideas?

Thanks.