Microsoft device manager shows 'Multimedia Audio Controller' as not installed.
This sounds like your motherboard on board sound interface (ensure it's turned off in the BIOS unless you actually need it on.)
The PCI1750 card should appear in the device manager under 'Adventech DA&C I/O cards' as a 'Advantech PCI1750S Device'. - Or it least it does as such on a XP box I've just checked. The PC was built by PSquared so didn't do the install myself - but from memory of rebuilding a Win2K box using the latest Adventech drivers downloaded from their website worked reasonably straighforwardly, though I seem to recall having to use their set-up utility to manually specfiy which model card you had installed, it's not totally plug and play.
Myriad user since 1998, now custodian of dozens of Myriad,Autotrack, Powerlog and Scoop boxes of many different flavours.