Ipod won't turn on and technology failing as we speak!

My ipod refuses to turn on after I'd been listening to it half an hour before, it takes ages for my laptop to recognise it and when itunes recognises it, it freezes, I've had a message saying my ipod's corrupted but itunes froze before I could restore it!

I bought it from ebay, it's an ipod nano 5th gen so I have no warranty and repairs would cost what I paid for it (and more!) I bought it in November/December, so don't know where I stand with the ebay seller either.

Please help as I am a total novice at apple technology (and internet in general). Thanks x