Hi Mike,
tks for the start of this post.
Please post exactly the settings you have attempted with Windows10.
For Example...
Did you turn off your AV scanner on the SDE folder?
Did you turn off databit tracking on the sde folder in win10?
Did you optimise for 8/16 bit application running in 32bit Thunk on 64 bit win10?
Did you run it with any windows 10 compatibility modes and what privileges?
What video settings did you use?
What network settings did you use, did you turn off ipv6 and optimise the tcp ipv4 stack?
Etc...
cheers