How to activate sound in windows vista ?

I want to activate sound card. When I right-click the card on Device Management i am not getting activate option. What should i do to activate Sound ? please help me

Thanks

Open Device Manager by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Maintenance, and then clicking Device Manager. Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

Expand the Sound, video and game controllers category. If a sound card is listed, you have one installed. If no sound card is listed, You will need to install one.

If there is a yellow question mark next to the name of the sound card, there might be a problem. Right-click the name of the sound card, and then click Properties.

Click the General tab, and then look in the Device status box to identify problems with the sound card.

Install the latest driver for your sound card.

• Open Device Manager by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Maintenance, and then clicking Device Manager.
  
• In Device Manager, locate your sound card under Sound, video and game controllers, and then double-click the device name.
  
• Click the Driver tab, and then click Update Driver.