Brightness slider not working in JKA

[RebornKyle]

So recently I moved my files from my old laptop to this new one, among them the old games like Jedi Academy I have downloaded. All work properly EXCEPT JKA, as its brightness slider will not work. I also tried setting it manually with the r_gamma cvar in console, to also no effect. What would be the issue causing this? Everything else is fine, just this problem. I am also using Windows for both, so it couldn't be an OS issue, but I wouldn't expect the brightness to be affected by that anyway.