Why does my ipod video keep crashing?

I have a 5th generation ipod video 30GB and it was working fine but now it crashes constantly, the display will just freeze up and won't respond to anything. I perform a hard reset and it does it again randomly, I've run diagnostics on it and everything checks out ok. it doesn't show the sad face or the HDD crash error screen and I've restored it with itunes 3 times now. yesterday I reset it and then just left it alone and the battery completely died. it even crashed while it was charging. I've only had it for a week and never dropped it or abused it, so what could it be?