A grayed out device can indicate a disabled, absent or damaged/broken device.
Check if your sound is disabled. If it is, use the "Enable" button or check box.
The effect should be immediate, but restart just to be sure.
Check the IRQ and address range of the sound device and all other diveces. There may be a conflict.
If there is a conflict, you can manualy set the IRQ and address range to resolve the conflict. (this is a legacy process, remember the good old DOS days...)
Finaly, ther is the possibility that there is a physical problem with the sound device. You can't repair that on a laptop. On a desktop, you'd need to replace the sound card.
Electro, September 2013