Songs Show up in iTunes but not on iPod

I am using Windows XP, I have a 80GB video iPod. My problem is that my iPod itself, everytime I turn it on, starts up like it has been reset (at the Choose language screen) and there are no songs or playlists or artists or anything on it at all. I feared that I had reset my iPod accidentally and lost everything, but on my iTunes, all of my music and playlists are still there like nothing happened. I don't want to sync it, because all of my music is on my iPod and not on my computer (I use my iPod as a sort of external harddrive). I really am at a loss as to what to do. I'd like to be able to listen to music on my iPod, not just through my computer. Obviously I didn't lose the data, it's on the iPod, but for some reason the iPod itself does not recognize that.