Thank you for your answer,
i tried it. It tells me i don't have the permission to access.... although i set it on "run as admin" und comp mode WinXP SP 3. (DEP is still off and i am the admin user)
Also i don't have populous in C:\Program Files\.... installed, but instead in a Folder outside of the System-Folders. Especially with older games Win10 had problems if i had the games located there.
If you can get process monitor from https://technet.microsoft.com/en-us/sysinternals/bb545027.aspx
and attempt to run the version you're getting the permission denied error on with that logging file system requests, that might help.
Is the entire problem AMD/ATI related?
I am playing Populous 1 on my Surface Pro 4 using only the graphics processor of the Intel core i7 CPU. The game runs without a problem.
I am stucked now since ages hopelessly at map 140, so it surely works :-)
When I investigated my own crashing issues, I found the code could generate calls to direct3d createsurface which had flags set which should be mutually exclusive. I modded it to stop doing that, and my crashing went away. This could simply be a case of newer AMD drivers having stricter input checking than old ones. I'd caution against saying it's AMDs fault though, as strictly speaking I don't think they're doing anything wrong.