sound device problem

I have two operating system on my computer one is win xp and other one is win 98. my problem is that my comuter support sound card with win xp but not with win 98

What sound card is it? (version/type/year)
Have you checked the manufacturer's website for drivers?

Is it possible the card is so new that it isn't supported by Win98?

If you boot into Win98 and go into device manager does it "see" the sound card, and what is its status?

If it isn't there try installing it from within Win98.

If it is there and has a problem, use the trouble shooter to try to resolve it.

As MsM says, you should check for the latest Win98 drivers for it.

Cheers