Windows 10 on Mac Pro 4,1->5,1

Hello. I've installed Windows 10 on my Mac Pro 4,1->5,1. But when I try to install the BootCamp drivers, the Mac just shuts down in the middle of it. No error message, no nothing. No shut-down has ever occurred in OS X...

Specs:
2.66 Quad Xeon
NVIDIA GT120
16GB ram
stock HDD

Anyone else tried this?
Thank you.