Fortunately, this fucking windows partition I only keep for VR with my shitty Oculus Rift CV1 reminds me how fucked up the alternative is. I can't fucking wait to get a Steam Frame and ditch it.
Out of curiosity what were the old and new GPUs?
That's a particularly lengthy effort, even for Windows, so I'm wondering if you switched from nvidia to AMD or something major like that. Only thing I would have done differently is uninstall the old graphics driver before switching the hardware - but that is perhaps a very old expectation, so I don't know that it'd be reasonable in your case