Check your BIOS settings. Also, move the soundcard to another slot. In the BIOS tell it redetect Plug N Play devices. Arrrrrgh. I can't think of the setting. It makes the computer update the ESCD (all the IRQ and DMA and so forth).
Also, you might just install the drivers manually (without Windows prompting you). Setting --> Control Panel --> Add/Remove Hardware --> Have Disk --> browse to your driver CD