Go to device mangager (right click my computer, hit properties. click on hardware tab then device manager.
look for any ones with a ? symbol next to them.
Are you sure that your speakers are good?
ALSO, go into your bios and try to enable this line:
Device Type 2=Sound, Disabled
I dunno why it says disabled.. Poke around and see if you can make it enabled
Be careful what you mess with though
Good luck,
wng
I agree with wng_z3r0 about setting your bios and checking your device manger. Beleive it or not though I have had many calls with people saying they have lost audio. I tell them to see if they have a speaker icon in their system tray. If so unmute the audio. If not go to control panel select sounds and multimedia and check all the volumes, and make sure you have the correct device selected. If al the above fail then download an updated driver (here you may even try to install it just to see if it works) try deleting your sound, video and game controllers in control panel-device manager. Reboot and let windows find you sound card and use the new drivers. If windows does not find it I suspect you have incorrect bios settings. Nevertheless, go ahead and choose you own device and select have disk. Then use the new drivers.
So if your bios IS correct, you have updated drivers, you have uninstalled and reinstall your card, then I suspect your card is bad. Search for application that check harware at that point.
Ok I am out of breath LOL. Good luck!
Not sure if this will help, but I had a similar issue with Sigmatel audio not being recognized with XP Pro after upgrading from Media Center edition.
I had to go to BIOS, and Onboard Devices, and make sure Integrated Audio was ON.
I also know windows didn't recognize it until i installed Service Pack 2.
Sorry if this is off-topic, just trying to throw some info out there.
Good luck,
wng