So I bought this used Pismo off of eBay. The guy said it had a bad motherboard (diagnosed by a local, non-apple-affiliated technician) and included a replacement. He was right that the unit would not respond at all with the old motherboard so I installed the new one. Now when I hit the power key very little happens. The screen does not turn on and the hard drive does not spin up (known good drive). When you push the caps lock and number lock keys though, they both light up. Then if you hold the power key for 10 secs and try again they don't, so the unit is turning on, but not doing much beyond that.
Any advice as to what the next step should be?