No Sound Device-RealTek AC'97 drivers enabled but not started

The Sounds and Audio Devices CPL shows the Volume, Audio and Voice tabs as greyed out with no devices shown selected.

Under Device Manager, Realtek AC'97 Audio is listed under the "Sounds, Video and Game controllers", and it's property sheet shows under "General" that it is enabled and working properly. It is also enabled in BIOS.
Under Realtek AC'97 Audio Properties CPL, the "properties" tab lists Realtek
AC'97 under "Audio, Midi, and Mixer" devices entries (which it should), and checking each properties I find that "use audio for this device" is checked for each one, but each one's status says "Driver is enabled, but has not been started".
How do I get Windows XP (Home edition, SP1), drivers to work again?

 

first update your OS,than we can talk about solution.So run SP2,other updates,and post info for your comp.OK?