My PC doesn't recognize my iPod Touch

I just got my iPod touch for my 16th birthday from the pawn shop up the street. I was really excited when i got it, but when i plugged it up to my computer and downloaded iTunes, it doesn't recognize my ipod under "devices" at all. I looked to see if windows media player would recognize it and that didn't either.

It's very confusing to me though, because I know the cord is working because when i plug it into my computer it makes a ding sound and it pops up on my iPod that it's charging. I tried to read up on it and so far, have just gotten a bunch of dead ends. I have my iTunes updated all the way... I don't know whats wrong with it.

All I want to know is how to fix my iPod so that my computer recognizes it and I can sync music onto it. Please help me! Thanks!