Ok, try this. Go into the device manager and just uninstall your sound card. Go to the company's web site and get the latest driver for your card. If the driver isn't an executable (.exe) file, then it will usually be a zipped directory containing 2 or 3 files. Chances are if you tell the site you need the drivers for 98 it will.
Click on the "Add new hardware" icon in the control panel. This should bring up a wizard that will either have you input the new device manually or detect it itself; have it detect it itself. At this point it should say something along the lines of "found new multimedia device". It will then ask you if you want to have it search for the best driver or you can tell it the location of the driver you downloaded; tell it the location manually. Click on browse and navigate to the .inf file (your driver).
After restarting you should be all set, although there is a chance that the hardware wizard will want the Win 98SE CD, so make sure you have it handy.
Hope that helps.