Technical questions - sound & refresh

[HJ]

I just got a new system yesterday, and finally had the chance to install Doms today. However, I've been experiencing some technical problems with the game, namely:

1) The sound is stuttering. There are some sort of crackling noises when the music plays, as if the speakers went bad, but I have no problems with other games or audio files.

2) The refresh rate stays at the 60Hz even though my desktop at the same resolution (1024/768) is at 85Hz. Is there any way that I can adjust the refresh rate in the full-screen application?

Thanks for the replies, your time is appreciated.

Specs:
Athlon XP 2600+
Radeon 9600 XT
1Gb RAM
Gigabyte 7N400 Pro2 MoBo
onboard nForce2 audio
Windows XP Pro
All the latest drivers

Cheers,