After installing "reinstallation CD MS
Ok. This may or may not be a software issue, the info I give you will take care of it, either way, ok?
First, lets make sure that the audio service just hasn't stopped, ok?
Click start, then click run
next, type services.msc
this will bring up the services list, go to the bottom of the list.
you will see it say Windows Audio.
click on it 1 time.
On the left hand side it will either give you the choices of stop and restart service, or it will just say start service.
Click start, or restart, depending on which option there is.
Ifit starts all the way. close all programs and reboot, this should re-enable your sound drivers.
If not it will say something to the effect of " cannot start due to driver failure"
If it says anything like that, or if aftere doing the first thing doesn't give you sound, then you will need to download a new set of audio drivers.
go to : http://www,realtek.com/
Click on the download tab in the middle of the top of the page.
Follow the links for audio drivers
It will eventually get you to the download page, where you can select which operating system that you have, and if you want a zip file, or an exe file.
I always just take the xex version, that way I don't have to remember whee the zip files extracted to.
Run the download, and when it's done, just reboot the computer.
This should take care of your sound problem!