Bringing back the sound

Go to settings/control panel/multi-media/
On the audio tab, make sure the box to show volume control on taskbar is checked.

You should now be able to access the volume control window from the speaker icon on the taskbar.

Alternately, there may be a seperate volume control / mixer under the utilities for your sound card.

Okay, the next step is to remove and restore the volume control.

Go to Control Panel, Add/Remove Programs,
Windows Setup Tab,
Scroll down, and select Muti-Media.
Click on details,
Scrolle down to Volume control.
If it is checked, uncheck it.
Click apply, and re-boot.

Go back to the Muti-media options,
Select Volume control,
Click apply,
And reboot.

You should now have the option to use the volume control under control panel, sound.

If not, the next step would be to remove any sound card related programs from add/remove programs.
Remove the sound card and related devices from device manager,
re-boot, and allow windows to re-install the sound card drivers.

Chas

Okay,

Now, it's time for more details.

What version of windows?
DirectX version?
Mother-board?
Driver revision?
Soundcard?
Driver revision?
Source of driver file?
Other plug-in cards?

The other option is a corrupt file, or registry entry.
If you have W98, you can run sfc (system file checker) to look for changed, corrupt or missing system files.

Bad registry entries are tougher.
Unless you are familier with the registry, or willing to risk needing to wipe the drive and re-install windows, I don't recommend random registry edits.

Chas