iPod won't connect to computer.

When I plug in my iPod, the iPod registers it's been plugged into a computer, as it says "do not disconnect" and then starts charging after a few minutes. The computer on the other hand seems to notice at all the an iPod is plugged in. Nothing pops up and if I go file-->devices everything is still all grayed out. I've tried with 2 different iPods now (a 5th generation nano and 5th generation classic) so I don't think its the iPod that's the problem. The USB port works when I plug in my mouse so I don't think it's that either. The only thing I think it can be at this point is iTunes. What should I do. Am i missing something? Is there some way I could have set iTunes to not sync, if so, how do I check and fix this? I'm sort of scared to reinstall iTunes and stuff because of all my music and playlists. Theres some that isn't on the iPod and just on my computer.

Thanks!