I had a similar problem while installing XP with SP2. It couldn't install the driver for my sound card (YAMAHA PnP Codec). I guess it was coz the driver was outdated.
Even my computer service person couldn't get the sound going on XP.
Then on examining the details, I found that Windows XP was installing a default sound driver for my system that was included in its own driver files. [
driver.cab]
I copied the driver.cab folder, extracted all files, deleted the defaulting sound drivers, cabbed the remaining again renaming as '
driver.cab'.
Then,
1. I renamed the original
driver.cab in the XP system folder to driver1.cab
2. I copied the newly formed
driver.cab to the same folder, and deleted the original driver1.cab
3. I then reinstalled the YAMAHA sound driver which XP then recognised.
Maybe you are having the same problem of some default driver being installed instead of your sound card driver.
Just check the name as displayed on the 'Device Manager' under your sound card. If it is different from your sound card, you should try my method.
Hope it works. All the best.
P.S. : If you have a modem installed too, try installing your sound card before you install your modem. As it may be shared.