Apple Device Driver not installed?

I'm assuming this is the reason why iTunes refuses to acknowledge my iPhone's presence:/

I'm running Windows Vista--I know, I know, this operating system sucks. But it won't allow the installation of every component in iTunes. Namely, Apple Device Driver. So I don't know what to do about this. I have to connect my phone, but it's not going to work unless I have that piece if Apple on my Computer and my computer apparently has an guest list, and Apple D. D. Is not on it.

You have to be an administrator on the computer not a guest because guest has no apple d.d. Ask the person who owns the computer for the password.

Actually I have a system running Vista x64 for quite some time and it runs better than many of my other computers (including XP and Windows 7 systems), so I don't agree that Vista is bad actually…

But regarding the apple driver, the admin comment is valid, best use a user account with admin rights to install. It can also make a difference if the device is plugged or not. Have you tried connecting the iphone and then installing iTunes?
Does the iPhone device show up in the Device Manager at all, even if an unknown device?