iPod iPod 1st Gen stuck at Apple Logo loop

[ak-78]

Hi, my iPod is stuck in apple logo loop when I connect battery to Logic board, I also hear drive spinning and clicking and apple logo appears/disappears in constant loop. My powerbook wont recognize it in iTunes neither in DiskUtility. I also tried connecting to my MacBook Pro with same results. After I try to reset it by moving the Hold switch firmly to the off position (Select and Manu buttons) it does nothing. However when I press (backward / forward buttons) screen goes to √ OK to Disconnect. Then it's stuck in this mode and it won't recognized by the computer and buttons won't do anything. I have to disconnect battery again and it takes back apple logo loop. I also tried to push Manu and Play, this time it shows battery symbol with exclamation point. What could it be, corrupted hdd? It's happened after I had to disconnect my iPod from PowerBook cause its crashed while syncing.