To add to the information above if I may, many players find that the installer will refuse to run on the root level of a volume, meaning just plain D. We do (usually) need to create a folder on D first and then select that one. It doesn't have to be called Program Files or Program Files (x86) exactly, it could be called just about anything, but that's usually what it takes for an installer to see the intended custom location as viable.
To be fair, we don't really install programs on the root level of C either or else we would have program files splattered all over the top level of the system drive. It's just that Windows tends to guide the installers to an already designated Program Files folder on the system drive when we install the default way.
