When you try to add the Volume icon, you receive:

Windows cannot display the volume control on the taskbar because the Volume Control program has not been installed. To install it use Add/Remove Programs in Control Panel.

If the Sndvol32.exe program is missing or damaged, your installation will exhibit this behavior.

To fix the problem:

1. Insert the Windows XP CD-ROM, holding down the SHIFT key to prevent AutoPlay.

2. Open a CMD prompt and type:

Expand <CD-ROM_Drive>:\i386\sndvol32.ex_ %windir%\system32\dllcache\sndvol32.exe
Expand <CD-ROM_Drive>:\i386\sndvol32.ex_ %windir%\system32\sndvol32.exe

3. Add the Volume icon.