I'm getting a bit stressed out here, too. Had to set up my system from scratch for unrelated stepping-on-laptop-in-the-dark issues, and I am getting nowhere and nowhere fast.
Here's what I've tried:
Install iTunes - Apple Mobile Device was missing.
Install iTunes, move old iTunes folder to new location - since Apple Mobile Device was still missing, it still didn't work.
Install iTunes, import old folder - same
Install iTunes with old folder in place - Old folder got integrated, Apple Mobile Devices got installed - iPhone was not recognized, because it "needed the latest version" of iTunes. Installing Upgrade failed.
Install Apple Mobile Device manually as stated above (before and after iTunes installation) - Installation failed without explanation.
I always uninstalled iTunes as per the instructions from this site. I'm running a Windows 7 64 Bit system with all the latest updates, freshly installed and running smoothly. In the course of all of these installations I have downloaded iTunes64setup many, many times. Surely in the double digits.
If Apple at least let me install an older version, maybe that would work, but all I can find is always the latest.
Samsung is sounding more and more promising...