AppleMobileDeviceSupport.msi - unable to download drivers to sync iphone

Installed and uninstalled and reinstalled itunes about 5 times but the same problem keeps happening - the computer is unable to recognize my iphone 3GS. My computer recently had to be restored to factory settings and I have updated all the software. It's an HP Pavilion running on MS Vista.

I have tried reseting the phone and the computer but it keeps coming back to a problem with AppleMobileDeviceSupport.msi

How do I fix this problem? I am not supper tech savvy but can follow instructions very well. I will be switching to a MAc Book Pro soon but I still need to fix this in the interim!

Help Please!