If the above hasn't helped and you have received this error:
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.
To resolve this issue, extract a new copy of Sndvol32.exe from the Windows XP CD to the system_root \System32 folder on your computer's hard disk. To do this, follow these steps:
Start/Run/CMD. In the command prompt window type:
X: (where X is your CD Drive letter)
CD \I386
Then use the expand command: expand -r sndvol32.ex_ c:\windows\system32
Note: This assumes XP is installed on C: and that its installed in the Windows folder. If not, you'll need to adjust the command accordingly. Additionally, this must be an installable version of XP, not a "recovery CD".
Save Settings on Exit (use this reg edit) *see
note below*
http://www.kellys-korner-xp.com/regs_edits/savesettings.reg
*note*
To use any of these Regedits: Save the REG File to your hard disk. Double click it and answer yes to the import prompt. REG files can be viewed in Notepad by right clicking on the file and selecting Edit.