Hi! I'd remove the battery just to rule it out, and then reseat the RAM, and try one module at a time in one slot, and then the other, both to rule out each memory module, and also each memory slot. I would reset the PMU again with each RAM/slot configuration, and reset the PRAM each time as well.
Does the screen come on at all, or is it black the whole time? If it's black, do you see a faint Apple image when you shine a flashlight through the Apple symbol from the back? If so, this could either indicate a bad inverter cable, or a bad screen. Next I would connect the machine to an external display. If the external display works, you may have a dead screen, or the screen cabling may be failing. If it doesn't work, you may be experiencing a video chip issue, or a logic board issue.
The fact that it won't eject the CD is suspicious. What CD is in the drive? It's a longshot, but it could be that the CD is hanging the system. Try holding down the option key while powering on to boot into option mode, and see if the option menu pops up on the screen.
Let us know how all this goes, and we can go from there.
Thanks!