...there are a couple of ways to approach the problem..
First, since you haven't told us much about your computer (it's not your forum profile either), then you could visit the computer manufacturer's website, then check for driver downloads for your particular model number..Make sure the driver is one that works for Windows XP.
Next, you can check the specific sound card model on your computer and visit the sound card manufacturer's site, then download and install the XP driver from there. To determine you sound card device type and driver version, RIGHT click on "My Computer", choose "Properties", then click on the "Hardware" tab, then click on the "Device Manager" button. When the Device Manager window opens, click on the + sign next to the "Sound, video, and game controllers" listing to show a number of devices. Find your audio card device, then RIGHT click on the listing, choose "Properties". Once the Properties window loads, click on the "Driver" tab, then write down the EXACT name of the sound device, plus the "manufacturer/provider" name, then the "Driver version" and the "Driver date"..
You can now visit the provider's website and find the newest XP compliant driver for that card.
Hope this helps.
Grif