Cannot get sound driver working with Inspiron 1501

I've been trying to get this driver working for several hours now.  I recently installed Windows XP sp3, and cannot get the sound driver working.  I tried installing the Sigmtael STAC 92XX C-Major HD Audio but I get an error message saying that "This system does not support the driver you are attempting to install".  I found a similar thread, and followed the instructions to install Dell Notebook System Software, AMD processor driver, and Sigmatel audio driver, in that order, but I had no luck with that.  In Device Manager, I believe that the sound card is under "Other devices" as "PCI Device".  I tried Update Driver with Windows Update, but had no luck with that either.  Does anyone have any suggestions?