What OS are you running this on?
I've got my eye on, "War in the Pacific: Admiral's Edition", but I'm wondering if it will run on my Windows 10 64-bit OS.
I have, "Gary Grigsby's War in the West" and it runs perfect. No compatibility mode, nothing. It just works. All I did was disable Steam Cloud saves, VR Theater, and Steam Overlay under, "Properties" in the Steam interface, and then did something that I learned from, "Battlestations: Midway". I restarted my computer before touching the new installation.
I figured out through trial and error that, "Battlestations: Midway" is dead on arrival on my modern machine unless I restart before launching. And it will not forgive you. You'll have to uninstall, clean up, and reinstall if you dare touch the game before re-starting. If you re-start before launching, it works perfectly. So I did the same with, "War in the West" and didn't have any problems like so many others have.
Anyway, I'm not sure, but I think, "War in the Pacific" runs on approximately the same engine as, "War in the West". So there may be hope for it to run on Windows 10 64-bit.