My Ipod Touch keeps crashing...

I have a 2nd Gen, 32GB Ipod Touch. This only seems to happen when I have not been using my ipod for a few hours, it never happens while I am using it :/. I unlock it and then it is suddenly frozen on the lock screen, as in it does not respond when I try to slide to open it, but it still shows the correct time and I can still lock it again, but the touch screen is just not responding. So I try holding the power and home button until the Apple logo appears. Yes, the Apple logo appears, fine. But then I get the screen that tells me to connect it up to Itunes (the USB symbol), so I connect it up, and it's randomly deleted EVERYTHING off my Ipod, including anything I may have bought, so I've lost that too. :/ So I have to restore from backup, and it takes all day to put everything back on. I even tried setting it up as a new Ipod, in case there was something wrong with the backup.
The next day - all of this happens again. It's a nightmare!
Please help!
Sarah x