Hardware ::ipod Connect To An PC Now It Gets Corrupt And Cannot Connect To Any Other System?

What i did was open the ipod through mycomputer (windows XP) and cut the folder that contains all my music and pasted it into mydocuments so i had full amount of memory on my ipod to use it as a memory device. I gave it to my friend to put some videos into my ipod again through mycomputer. He didnt allow the ipod to sync on his itunes. Now i have it back i plugged it into my pc and my itunes couldnt pick it up and neither can mycomputer. I left it plugged in and restarted my pc when it booted up i opened itunes and it was sort of froze, after leaving it for a minute or two my ipod cam e up on itunes but it said it was corrupt. I ran the restore over night as it was taking along time and when i cam back this morning it was still doing it! Whats wrong with my ipod?! is there any other way to system reset it? do you think my mate should have synced it with his pc?