I have been building cheap PCs for friends etc, and I keep running into problems with the motherboard audio not working.
The problem has happened with several different brands of motherboards. All of the machines are "barebones" PCs from various manufacturers, including Asus, Biostar, and Intel. All of these are new machines, which get Windows XP or XP Pro installed from new OEM discs.
Upon assembly, every function but audio can be brought to life. Using the disc that comes with the motherboard won't work; some load normally; some indicate failure to install audio codecs. Downloading drivers right from the board manufacturer worked in one case, but has failed on the rest. Windows troubleshooters didn't suggest anything I hadn't tried. In some cases, no audio devices are detected, even after downloading drivers from the manufacturer. In others, it shows the audio as working correctly according to windows, but no sound. There have been no instances of plugging anything wrong inside. The problem arises before even attempting to connect CD/DVD audio cables; and neither is a front panel audio connector issue affecting this.
On three of the machines I ended up installing a PCI soundcard to make up for it, which is annoying on motherboards that boast N-channel sound etc. Now I have a machine that won't make sound even with a sound card.
Sound seems to be the one aspect of assembling PCs that I have not yet mastered. Does anyone have suggestions?