Well, a year later I finally decided to really tackle this problem and I posted it in Computing Net forums today. And I have my volume icon back, today! Very great service.
My computer did not come with a Windows XP CD, so I tried to find the file sndvol32.exe on my computer but no success even using the Search.
Then this person pointed me to this site,
www.relaxingsoftware.com/sndvol32.exe so I downloaded the file, and followed the rest of their instructions.
And voila, I have my volume icon back. Woohoo!
