Are both sound cards presently installed in the PC? Is one of them actually an on-the-motherboard sound device? Did you have drivers for both of them installed and working before? (That is, could you choose which one to use for various sound functions?) Do you want both to be working?

You could try running the Add New Hardware wizard, and telling it what hardware you have and pointing it to the location of your driver files. If there is a resource conflict this might not work, but it is worth a try.