You have no drivers loaded for your sound. From the page you linked to with info about that system, it looks like you would need these
drivers for Realtek HD sound.
You may also need other software from Realtek too so read around the site some. You could further look into it more by opening the case and looking at the motherboard. Look for any chips on the motherboard that are Realtek chips and write the numbers down that are on the chip or chips then go to the Reaktek web site and look up the chip numbers and download the drivers for the chip numbers you have. This way you are sure you have the right drivers for the chips that are on the motherboard.
An easier fix may be to just get a cheap C-media chipped sound card (or the way better Chaintech AV-710 card) and install that. Realtek sound is about at the bottom of the pile when it comes to sound chipsets. I do not about this HD sound but regular Realtek chips are just basic Windows sound sound chips and that is about all they are good for.
Added:
Looking again that web page you linked to about info on the motherboard shows;
# Audio Chipset:
* Support Azalia Audio codec with Intel ICH6 embedded Audio controller that includes line-in, line-out (8 Channel), microphone-in, CD-in, SPDIF
* Using Realtek Azalia Audio Codec ALC880
So the drivers maybe Intel ICH6 chipset drivers. You may want to check into that to.
Added again:
I found these drivers that say; "Click here to download the drivers for your Realtek High Definition Audio (Azalia) sound card." Here is the link;
http://support.pcworld.co.uk/Uploads/%7...28-43c6-8220-3ebad33008b8%7D/Sound.zip
I would try these drivers first.
This may also be helpful with more info on that machine.
http://support.pcworld.co.uk/layout.asp...{8e9e68e6-c0d3-4c4a-b214-1bc28d1e562b}