I fixed it. The card diddnt like some windows aero features and for some reason caused it to crash.
I turned these features off in safe mode and it now works perfectly. I've got it in game running smooth as butter.*
So, This is kind of a long story.
TLDR: GPU works in my main PC but not in my secondary.
Non working with GPU:
Asus H110i Mini ITX MOBO
16GB 2333mhz RAM
(New line)CX650M PSU
Working with GPU:
R7 2700X CPU
X470 Prime -F MOBO
16GB 3333Mhz RAM
EVGA G1000 PSU
So now for the longer version.
I bought an RX 480 on eBay for £30 "non working, black screen when in windows". Every other time I've seen this problem it's either A: Dead bios. B: dying or crappy PSU.
So I bought it and threw it in my main PC, low and behold it works.
The reason I bought this is for my dedicated VR PC as it's been built totally on the cheap (£120 with the GPU).
Once I got the card, I took out my 1080Ti, Nuked the drivers, put the 480 in and got drivers installed no fuss, and boom GPU works. Played Overwatch at 1440p just fine, so cleaner my driver's, put my main PC back together and went to put it in the mini PC, and as soon as it got into windows after about 5 seconds it black screened.
So with that I thought that maybe my PSU was dead, it worked with my R9 280, but that's years old and no where near as demanding, I was dealing with an old line CX750 Here so, I got a new line PSU that's brand new from my girlfriend (it was used for about 2 weeks before being replaced with a EVGA P1000 so it's fine)
I've tried a lot here, I've got drivers installed by having the CPU as the output monitor and it just crashes. I'm at the point here where I genuinely do not know if it's windows fuckery, or there is something wrong.
Any ideas or next steps for me to go with here??