(re: Need help with GK I on Win 2000!!!) Actually I have been running Gabriel Knight 1 on XP on a P3-600 Mhz, 128 Megs RAM just using VDM sound, perfectly with speech etc. I never had any trouble setting it up, and both the Windows and DOS versions run great.
Win 98 would be certain to get the DOS version running, but you will not get digital sound effects or speech unless you have a legacy Sound Blaster card installed.
My advice would be to do what I did and just upgrade to Win XP, and rebuild your machine (i.e. new software isntalls) from scratch.