I had this problem. I just installed the drivers onto my hard drive, and then went into device driver and selected the properties for the sound card (windows2000 recognized it as some other name) and selected search for a better driver, and it found the ones on my hard drive and detected the mx400. You should also run windows update, as I got updated drivers from there. You can do that at
www.windowsupdate.com . You may not even have to install the drivers on you hard drive if you have the CD in the CD-ROM. If you can't get the drivers on you HD from the CD, try dowloading them from the vendor site.
The problem is my sound quality isn't pure (with headphones mp3's and CD's sometimes have a static sound in the background). I'm looking for a new sound card now.