I just bought a Galaxy 500 and when I push and hold the power button, it does not seem to be working. Does the battery need to be completely charged up to show anything?
The battery does not need to be fully charged for the phone to turn on. It should turn on when you press and hold the power button like you did. Bring it to the store where you purchased it from or an authorized Samsung repair center to have it checked or replaced since you just bought it.