IPHONE 3GS SYNC PROBLEMS WINDOWS 7!?

I bought a HP TouchSmart (x64) running with windows 7, when I tried to sync my iphone 3gS 8GB with the latest version of itunes 10.1 x64 (the right version for my pc) it doesn't complete the synchronization. I've tried everything, downloading an older version of itunes (to 8 and 9) checking my usb connections, disabling bonjour.. everything and didn't work. I also connected my Itouch 3g and it synchronized normally, only with the iphone happens that. I read in some forums that this problem gets fixed updating the latest version of the BIOS, but I heard it could make fail the whole computer. what should i do? Because I'm running out of ideas.