If you run into a problem uninstall nvidia's drivers, go into your processes and kill everything nvidia and try again. This is what I had to do. After the reboot, I didn't feel like waiting on windows update so I installed the driver I previously downloaded from nvidia's website (353.62) and chose for it to do a clean install. No issues since.
Ah so this is why you didn't have quite the same problem I had. When I was battling this this morning, Nvidia's website only had 353.30, while Windows Update had the new 353.62. I couldn't just install Nvidia's package because it was seen as older than the Windows Update version so it would constantly try to re-install it.
It didn't care if I had FF running and was obviously using the graphics card. It just initiated the install and disabled my graphics card anyway, crashing everything. Excellent stuff.
It's the only problem I've had with Windows 10 so far though, been smooth otherwise.
It's in tiny writing at the bottom, but just to re-iterate: Group Policy stuff only works if you're running Professional/Enterprise versions of Windows. Interesting if that's all it takes to disable the mandatory installs though. I figured that feature would be gone. Businesses are supposed to be using Enterprise, which connects via WSUS (locally hosted Windows Update) which circumvents this stuff anyway.