Cannot restore or recover ipod Classic 80gb
You can try to diagnose the problem with the diagnostic mode.

To enter the diagnostic mode, press the folowing key when the apple logo appears after a reset :

iPod 1G, 2G et 3G, press the keys for 5 seconds : 


"back"
"next"
"select"


iPod 4G, 5G, mini et nano,  press the keys for 5 seconds :


"back"
"select"


In the diagnotic mode, you can navigate in the menus with the back/next keys and launch a bunch of test.