I had a Monster Sound MX300 in my system for a year and a half, then I upgraded to Windows 2000. Nothing but trouble. I'm just telling you that you're not alone..
At first, I was using a hacked set of drivers from Vortex of Sound:
http://www.vortexofsound.com/drivers/drv_v2wdm.htm
They worked just fine on my Abit BE6 motherboard with a P3-500. But when I upgraded to an Abit KT7-RAID with an Athlon Gigahertz, then everything in the audio department went to hell.
I tried the hacked drivers (because I like the Aureal 10-band equalizer!). They played for about 10 seconds, or until I decided to do something with my computer -- like move the mouse..
Then, I backed down and tried Win2000's Aureal drivers. Same thing. No audio after 10 or so seconds..
I did some research and found that the KT7-RAID uses ACPI, and the BE6 didn't. (Well, the BE6 supports it, but apparently not in the same way as the KT7-RAID.) Anyway, the MX300 didn't like the fact that ACPI put seven of my devices on IRQ 11. Because the KT7-RAID will not let me disable ACPI, I couldn't change the IRQ on the MX300.
Therefore, no sound. I need sound!
Therefore, no MX300. I decided to back down again and stoop so low as to get a Sound Blaster Live.
My computer makes sound now, but I don't have a 10-band equalizer. That's the only thing I miss..
-Quazi