I used to own jk a year ago and i had the same problem.
Change the screen resulotion and it will be fixed.
You can turn on and off the 3d acclearation and stuff.
I had the same problem with other games and it was the resolution being the culprit.
Jedi Knight Dark Forces 2 Mod Project Leader and Console and PC Gamer
Games i'm looking forward to:
-Red Faction Guerrilla
-Fallout New Vegas