Right click on "my comuter", then "properties". Choose the "hardware" tab, and finally click on "Device Manager". Scroll down until you see "sound, video and game controllers" (or similar). Click on the + to the left to expand. You will see something like "Realtek High Definition Driver" (there may be two different ones, in which case do the following for each one). Highlight and right click on this. Choose "update driver". Hopefully this will find an updated driver which will get you rolling again. If it does not, go back and right click again, this time choosing "uninstall driver". Then reboot the machine. When rebooted, the computer will come up with "found new hardware". Let it reinstall everything, and hopefully you will have sound again. Hope this helps.