Wirelessly posted (Mozilla/5.0 (Linux; U; Android 2.2; en-us; DROID2 Build/VZW) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1 854X480 motorola DROID2)
No, you don't need the battery cover. When you hold power, you don't see the keypad light flash? Typically, when a flip phone is broken in half, it only rips the flex cable, which shouldn't affect phone power.
From the first time that I put the phone back together (flip came apart, battery was out) and then tried to turn it on, I've seen no light, flash, nothing. Thinking maybe the charge was affected, I plugged it in. No change. Holding down the off key doesn't generate any change.
If the phone is really dead, my question is what is the likelihood it is a battery issue (it was 3 years old - could the impact have damaged it?) or it is an internal circuitry issue. Replacing batter easy and cheap. The other, well, not so easy.
Google and try to rebuild the cell if not give it for repairing, the local stores sometime do a neat job and doesn't cost too much either. If the problem still shows after that, I think you'll have to go for a new one and this time tell the wife it's her's too