Front and rear audio ports not wrking

My friend has this computer which is about six years old. It is running Windows 7, until a few days back when the audio ports suddenly stopped working. He now cannot connect a speaker or use a headphone. I tried reinstalling the drivers with no result. Then we tried a Linux live CD. Still these was no sound. What could be the problem? If it is hardware related, is there a solution I can try?
Thanks.

Have you checked that onboard audio is enabled in the bios? If it is a hardware problem you can always use a pci/pci-e or a usb audio card.

Sometimes you can have multiple audio devices and it may be possible that you have the wrong one specified. Go into your sound settings and see what you have configured as your output device. I don’t remember enough about where the settings are in Windows 7, but I think you can get to sound settings by right clicking on the speaker icon on the taskbar. If that doesn’t work go to the control panel and click on the sound settings. You should also check the bios settings as kyrcy suggested.

I also agree with checking the BIOS setup. A work colleague had a similar issue a while back and after spending some time troubleshooting, I eventually checked the BIOS setup to find the onboard sound was disabled.