Are U sure is the correct sound driver? U should download right from your system manufactures, selecting correct PC model and OS. U can see if updates are available also. Uninstall it and install it again.
Make sure Windows audio service is started, (start>run>msconfig) , that chipset drivers are installed, that aren't any sound-related errors in Device manager, and see if the bios recognize it.
Check if Sound and audio devices in control panel under audio has a device selected, or try and select it, check speakers settings, and make sure the Place volume icon on taskbar is checked.
What PC do U have or what sound card?