iMac G4 FlatPanel Boot Issues

ok, here is the issue:

iMac G4 1.25Ghz- Upgraded the RAM, now I can hear the chime when it boots, but nothing else happens. I can not reset PRAM because the keyboard isnt recognized. The mouse will light up, but thats about it. I have replaced the RAM with the origonal, reset the PMU, checked all connections with no luck. Im hoping someone here would have a clue. Id be willing to pay for a correct answer.