My computer has been running fine, then today, the battery got low and turned off. I plugged it in and turned it on, but all I got was the initial internal sound of the system attempting to boot up (not the Apple Chime, but the actual internals ,I think the CD Drive or something), and a very quick flicker from the screen, but it wont boot up. I've tried resetting the PRAM, the SMC, swapped out RAM and Hard Drive with nothing different. I know its an old computer, but I just stuck an SSD in it and it was working amazing. Any suggestions? I know of no reason why it would be something like water damage since it hasn't gotten wet.