iPod seems dead, with only showing a grey screen.

Recently I replaced the battery of my IPod Classic 80GB, I ended up replacing the screen too. Afterwards the device became practically unresponsive. It shows me a grey screen, and that for only a few seconds. The hard drive isn’t spinning up either. It seems to restart, but that makes no difference. Connecting it to a computer changes nothing, and the Computer/ ITunes don’t recognize anything. Is the thing just done for? I’m not sure if I should just give up on it, as the device has had many many years of use.