Iphone 4s won't sync to Itunes?

I just got an Iphone 4s. When I plug it in to my computer for the first time to sync with itunes, it's not recognized and does not automatically start syncing my music, apps, etc. It doesn't come up on the left hand side of the itunes window under devices either. I know the USB is fine as it charges and the Windows "Open to View Files" window comes up as soon as I connect it to my computer. I've tried closing/re-opening itunes, restarting my computer, and unplugging/re-plugging my iphone 50 times but it still won't sync! Can anyone help? My computer has Windows 7 if that affects anything.

Have you tried rebooting w/o disconnecting the device? How long have you left it plugged in? Sometimes they need to be charged first.