I have a trusty ole 30gb but wanted to just buy certain parts to replace and upgrade. List of upgraded parts:

1. Click wheel

2. back casing

3. headphone and hold jacks

4. battery (original to 850mah)

5. hdd (from 30gb to 80gb)

All parts installed and I had the apple logo then sad iPod face then "battery very low" message and now Im getting absolutly nothing. Any help?