Volume control program not installed

All of a sudden, I realized that the volume icon no longer appears among the task bars and when I tried to add the icon to the task bar.  I got the message...

"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."

After googling around, the problem finally got resolved by the following steps provided at Microsoft website...

• Have the Windows XP CD ready in the drive (e.g., d)
• Go to command prompt (Start-> Run-> type in "cmd" next to open)
• Inside of the command prompt, enter 

1. d: (to switch to the d drive) and press enter
2. cd i386 (to switch to the i386 directory) and press enter
3. type in the following to copy the file sndvol32.exe into your the folder where the windows system files are placed--  expand sndvol32.ex_ c:\windows\system32\sndvol32.exe -- and press enter
4. Type in "exit" and press enter to exit the commend prompt

To add the volume icon, click on start-> Run-> and type in "mmsys.cpl" to launch the Sound and Audio Property window, click on the checkbox next to "Place volume icon in the taskbar".