"I checked the existing battery (which had never been replaced, as it was dated 11-1998) and it was completely dead. Do you think that the PRAM battery could be the cause of it not booting?"
In your previous Topic from 2 days ago, you indicated that you have already replaced the battery.
"Recently, I was using my powermac (About 1-2 weeks ago) and I went on vacation. I came back and it won't turn on. Everything's plugged in, and the power buttons and lights on the mobo light up. I can hear the HD spin up, and begin to read. But, I don't get any video. I've read that it could be the battery and so i replaced it, but it still won't turn on."
If you've already installed a new battery and that didn't restore normal operation, you need to consider other hardware component issues. A graphics card can go bad, leaving you with a black screen. Power supplies can and do fail, with no advance warning. I had that happen in one of my beige G3s. It worked normally the last time I used it, but a couple of months later, it was D.O.A. when I pressed the power button. You previously indicated that you've got a 512 MB DIMM installed in one of the memory slots, that's recognized as 256 MBs. This is expected, because the memory controller can't recognize high-density RAM. Even though the memory is recognized at ½ of its overall density, I wouldn't advise installing unsupported components on the motherboard, if you want trouble-free operation. You should only use a 16-chip, 256 MB DIMM, if you want 256 MBs of installed memory in any slot.
