iPod Classic 5th Gen - possible HD fault

Hi so I have a 5th gen iPod Classic 80GB which has been working fine since I bought it second hand.

Yesterday however it was not responding and I connected it to my laptop to resolve the issue and it came up as corrupted. I have had to put it into Disk Mode, followed by fully restoring it to factory settings.

this process has taken a long time to get to but eventually went through fully. now however it is fully restored when disconnected from my laptop. as soon as i plug it into my laptop it shows the screen status saying "Connected - Eject before disconnecting.". however instead of displaying the charger connection picture it shows the rotating sync symbol as if it is syncing, but this isnt the case.

just for reference the ipod also does not appear in itunes when it is connected to the laptop but does show up in my desktop as a removable disk. in addition, the ipod works as if it were new when disconnected.

everytime I disconnect the ipod and reconnect it to my laptop it repeats the process saying the ipod needs to be restored to factory settings even though i have just completed this process.

I have done some research on apple support and read about how to access the test mode on the iPod which shows diagnostics.

I have been at it for a fews hours now to resolve the issue but I am out of ideas of what to do.

could anyone help me with this rather frustrating problem?

many thanks,

Johnny