Apparently there is a problem with getting the iPhone to sync when using the new Microsoft Windows 7 operating system if you computer uses an Intel P55 Express Chipset.
According to an article on the iphone blog, over the past 6 weeks the Apple discussion boards have been clogged with numerous complaints on the problem, with most cases reporting that iTunes 9 for Windows will recognise the iPhone, but when attempting to sync they receive an error message.
So if you are suffering with this problem apparently there are a few things you can do to get around it, and have worked for some iPhone users, they are…use a USB port on a USB card which isn’t part of the P55…disable Bonjour…turn on C-state capability in BIOS…and delete the iPodDevices.xml from C:\Users username\AppDate\Local\AppleComputer\iTunes.
Let us know how you get along.