Monger,
This morning I went to this link you gave:
http://www2.driverguide.com/uploads/uploads13/14318.html, and got the file at that location. It contained four subfiles, including a driver, which I unzipped. Then I went to device manager and browsed to that specific file and said to update the driver with it. While copying it, it ran into 3 subfiles, for which it indicated that my current version was more recent and that the system recommended using that. I went along with it and said yes, OK. Nothing. Then, hoping that one of those files contained the corruption, I went back to device manager, and redid it, telling it "no" to those three files. However, setup could not find the file cmuninst.exe on the specified path. I skipped it. System rebooted, and I now have my windows sound back. What is the missing file?
Now that the sound issue is hopefully resolved, let's go back to updating the BIOS, if you still feel that is desirable. The very first window when booting up shows a release date of 1/10/2000S. However, further along, while it is looking for boot information from IDE-0, the BIOS date indicates 1995. What do you think? The so-called most current version of BIOS for my version is unzipped, sitting in c:unzipped. I also have it in a second place, from the download this morning from the above-referenced site.