Repairing Bootcamp doesn't fix drivers, fn keys don't work

So I should start by saying that the root of my problem is the FN keys. Mainly, they don't work. I installed Windows 7 on my late 2013 27" iMac (running OSX Yosemite) using Bootcamp 5.1. When I first installed it, my screen resolution was totally messed up, but oddly enough, my FN keys worked as they should (volume, brightness, eject, etc). To fix my screen problem, I installed an Nvidia graphics driver, which fixed my resolution and graphics, but I fear may have messed up the drivers and causes the FN keys to stop working. I say "fear" because I don't actually know. I don't know when the problem started exactly, but it was around then.

I should point out that everything else works perfectly. My wireless Apple mouse and keyboard work, except for the FN keys on the keyboard and the multi-touch on the mouse. So obviously it's a driver issue with the mouse and keyboard, but I haven't been able to fix it whatsoever. I've reinstalled Bootcamp 10+ times, reinstalled the drivers one by one, restarting after each time. Nothing works. I would normally just redo the Windows installation and start from page one again, but I've already got a bunch of software downloaded that took a long time to do so, so I'd prefer to have that as a last resort option.

Once again, the ONLY driver issues I'm having are:

- Magic Mouse multi-touch doesn't work
- Wirelss keyboard fn keys don't work (Volume, brightness, media controls, eject, etc)

And they are not fixed by reinstalling/repairing bootcamp or installing drivers individually from the Windows Support Software (5.1.5640).

Any help would be appreciated!