Client Hangups, Resolution, Graphics Issues

I'm having a really hard time with this old client. It refuses to alt+tab, always stuck on the top of my Windows 10 desktop -- enough that it's difficult to use Start or Task Manager. Client does not even respond to Alt+F4. I either have to restart or find some way to get back to Task Manager, which isn't easy. Also hangs at attempt to exit program through the options menu!

When I try to apply any graphical changes, it hangs with a black screen and white box in the middle. This includes resolution changes. The only way to rectify was manually editing Option.ini .

I don't know if this is a DirectX problem or what, because Windows 10 is compatible with X 9, 10, and 11. It would also be incredibly helpful if the client had a Windowed Mode, which is unavailable.

EDIT: Windowed mode also achieved through editing Option.ini and pressing Alt+Enter. It is so far more stable this way, though it freezes if I try to re-maximize .

Code:

StartupFullScreen=True

    <-------- add this at the end of Video section, and after game start push alt+enter