I forget the technical name for it (redbook audio?) but Jedi Knight uses CD audio on discs 1 & 2.
If your computer can play a music CD, then it should be able to play the JK music. The "format" is cd audio... not midi, not mp3.
The sound effects are in wav format.
Check to see if you can pop in an audio cd (circa 1997 if you want to get fancy) and have it play the music. If it works, then there's no reason why your JK1 music shouldn't work, if you're using the full legal version of the game (and say not some warez version with the music stripped out).
The game isn't "too old." People have gotten the music in Dark Forces 1 to work in XP, and that game is 2+ years older than JK1!