Alongside the iPhone firmware 2.1 Apple also released iTunes 8! However several Win Vista users have complained about the Blue Screen of Death (CRASH) upon using the latest version of Apple iTunes.
Here are a few possible workarounds:
How to Fix Vista Blue Screen problem with iTunes 8
1) Copy the usbaapl.sys from system32\drivers (from a Vista system running iTunes 7.x) to the same location on your desktop. Remove existing usbaapl.sys. Reinstall iTunes and try again!
2) Also Try: Uninstalling the Apple Mobile Device Support from your system. Now extract iTunes 7.7 installation exe with Winzip or WinRAR & reinstall only the AppleMobileDeviceSupport.MSI
And incase none of them work for you, wait for Apple to ship iTunes 8.1 😛
UPDATE: Apparently Apple has fixed the issue. Just uninstall Apple Mobile Device Support and iTunes, and download the latest release of iTunes from Apple.com !! Cheers