iphone not showing in itunes after windows reinstall

Hi
Can anybody please help me with this, I've tried googling the problem but no luck.

I freshly installed Windows XP onto a new hard drive, and have installed the latest version of iTunes (10.6.3.25). I had copied all my data from my old XP installation onto the new hard drive, including my iTunes directory (iphone sync data - apps, music) , so I just pointed iTunes at the directory and it happily loaded all my apps.
I also successfully reauthorised the computer - though it thinks this is the second computer I have authorised (even though I only have 1 computer, but it's a new hard drive and fresh OS installation) - does this make a difference to syncing? If so, is there some way I can convince iTunes that I actually only have one computer?
When I plugged my iphone 3GS in, Windows picks up the device, but iTunes doesn't.
So I uninstalled and reinstalled iTunes, and rebooted my computer, with no luck.

Does anyone know what is going on? Many thanks!

Edit: iphone is not jailbroken.
Edit: I have confirmed Apple Mobile Device Support is installed.

re: iphone not showing in itunes after windows reinstall

Hi icecapuk10,
Thanks for the reply.
I am running service pack 3.

gingertea

Moving to Apple support

Hi, I'm going to move this question over to the Apple support communities, which is where I probably should have put it in the first place. Thanks!