motherboard have,not sound on windows is 7?

if your computer came with a motherboard disc the sound drivers could be on it
click start control panel administrive tools computer management device manager sound video and game controllers could be a yellow question or exclamation mark ! ? or red x right click to re-install drivers
cnetdowload.com if these drivers are not suitable on the home page you should see the download software finder under that there will be a list platform, category sub category price from the category drop down list select drivers then from the price drop down list select free or which ever applies to your need
http://download.cnet.com/Realtek-AC-97-Driver-Windows-98-Me-2000-XP-2003/3000-2120_4-10238712.html

http://download.cnet.com/Realtek-High-Definition-Audio-Codec-Windows-Vista-Windows-7-32-bit/3000-2120_4-10788600.html

http://download.cnet.com/Realtek-High-Definition-Audio-Codec-Windows-Vista-Windows-7-32-bit/3000-2120_4-10788600.html

http://www.freeware-downloads.com/soundmax_integrated_digital_audio_driver_v.htm
SoundMax Integrated Digital Audio Driver v .

-----------------

if your computer came with a motherboard disc the sound drivers could be on it click start control panel administrive tools computer management device manager scroll to sound,video and game controllers you might see a yellow question mark? Right click to reinstall drivers or uninstall click start control panel sounds and audio,volume,advanced,speakers make sure you have selected the (((appropriate speakers))) also audio you will find 3 drop down lists make sure you have the correct settings there also click start control panel sounds and audio devices select advanced there might be a tick in the mute box untick it click start control panel sounds and audio devices you can adjust the volume there also select speaker volume you can change your settings there you can also tick in the box place icon in taskbar if his does not fix the problem have you tried this control panel sounds and audio,volume,advanced,speakers select the appropriate speakers from the drop down list or navigate to the device manager scroll to system devices + to expand,system speaker right click properties then select use this device (enable) also you might check the speakers plug/outlet is usually at the back of the computer you will have to open up the computer to check the lead attached to the rear of the input plug make sure the connection is good try cleaning your computer of dust using a fine air blower from a compressor making VERY sure that there is no MOISTURE in the air line specifically around the sound card and the CPU central processing unit dust causes static to build up in a computer