To elaborate, the sound suddenly changed a few days ago to become slow like a record being played at too slow a speed and also noticably distorted, like one of those sci-fi voice change toys. The machine was due for a reinstall of windows as this was an emergency rebuild of the system after the original motherboard (ASUS P4C800deluxe) died a month ago (safe mode uninstall of all incorrect drivers on first boot after build and then reboot). Rather than go through the annoyance of sorting through a 'dirty' system I decided to go for a full wipe then clean install of windows XP32pro. This did not solve the problem completely.
I have tried 3 different drivers for the onboard sound and none of them improves the situation.
Here's my hardware:
ASRock P4i65G with onboard C-media CMI9761A AC'97
Intel Northwood 'C' 3.0HT
1gb ram (memtest shows clean and functioning properly)
nVidia 7800GS agp
Seagate 200gb 7200.9 SATA (seatools reports functioning properly)
Logitech Fusion webcam/microphone on USB (disconnecting/uninstalling this has no effect)
No item is overclocked and the system has been otherwise stable since first build.
When I installed windows (my disk is sp1) I followed this with the Intel chipset drivers and sound drivers from the ASRock disc then Forceware 175.19, I had to uninstall the ForceWare as it is not compatible with sp1 (600x800 and 4bit colour only). After that I used update.microsoft.com until there were no updates left, then reinstalled FW175.19. Sound was normal at this point. I have added Kaspersky 2009, FlashGet 1.73, WinAce 2.69 WindowsLiveMessenger 8.5 and Steam.
When I tried to play one of my games via Steam I found the sound was again distorted so I have uninstalled everything back to the bare sp3 and drivers. Sound is still bad. This is where I then tried the 3 different sound drivers. the first from the motherboard disc, the second from update.microsoft.com and the third from ASRock's download site.
I am now stuck as I can't decide whether this is software (reinstall again from scratch) or hardware (RMA the new board).
Having no sound is no hinderance to work, but the wife uses Messenger to keep in touch with the family and video calls are a must as soon as possible.
I would say if you are getting the same issue and a windows reinstall and driver updates don't fix it, it's probably hardware. Grab a cheap 10 dollar pci sound card from newegg, pop that in and call it a day. Just don't get creative brand. I mean they are decent and all, but if you like a company that stops supporting the product because you upgrade to a newer windows version....With Vista I think they just stopped making drivers for a lot of cards, then someone else hacked the old ones to work and I think they were about to sue or something.
I tried an Ubuntu Live CD and that loaded with no errors and played all sound samples correctly. That clearly shows that there are no hardware problems. It is definitely a software problem . Now for a full reinstall of XP (again) but this time I shall check sound after each and every update and app install so I can trap this error.
The only thing I can think of would be a voltage issue on your PCI bridge. XP might put different demands on the hardware over Ubuntu, thus creating the distortion.
Also, when installing older versions of XP one sometimes encounters a problem where XP detects the wrong hardware and installs the wrong HAL during installation. This almost always results in more severe probllems than yours however. Slipstreaming also avoids that issue I think.