Hey, I seem to be having exactly the same problem. I had a windows xp home edition, a very good computer, extremely fast, for some time. After a while it broke, and me and my dad, having taken it apart and looked inside it, and alot more, simply couldn't make it start. We don't normally give up, but it seemed insolvable. So I took the pc apart, got all the bits out of it that I could. Then I tried putting it back together a few months later, to find it was because the procesor fans pins where broken, not holding it upright, and thus it was tilting, I fixed that and here I am now.
I only mentioned that as maybe taking it apart caused the problem, but I doubt it. Before it broke, the computers sound was fine, we had no sound card, but the motherboard sound system slots fitted our speaker cables into it, which worked. After fixing the computer, it started, but didnt work properly, so I re-installed windows xp on the machine. I did this, and everything works, aside from sound. Believe you me, I have tried everything in order to make it work. However, an interesting point, is, if you find some small speakers, which have no individual power supply to themselves, and have a usb port end on them, they DO work. So Your computer can probably do that, along with mine. However any speakers that have an individual power supply, and plug into an actual sound slot, do not work.
My theory, is that windows xp computers, as they have no sound card, come with an installed sound driver, that allows these 'built in' sound slots, be they on the front of the pc, or on the motherboard, to work.
This is because when I plug any sound device into any of these slots, my computer doesnt even register there something there. Not to mention read what the device is. If anyone has a solution, please send it to:
CRAMIE_THE_MAN_OF_STAN@HOTMAIL.COM, as I may not come to this site again, in the search for a solution. Thanks.
Oh I would also like to point out, I have been to system devices, set the sound device uploader to automatic and restarted it, to no avail. Im pretty sure I've tried every possible solution. Thanks again.