Sound Problems in WinXP

Hi,
I recently upgraded my OS from Win98Se to WInXP Pro. This happened as soon as I got the updated driver for my modem. I tried to upgraded few months ago without the uses of the modem then I uninstall winXp. At that time, my sound card was working fine. But now, after I installed the modem, it's working ok but then the sound is not. Right now, I can't play any Cd, can't play an audio file in Sound Scheme of WinXp...Eveytime I attemped to do so, I got an error message that says, for example when i tried to play a CD track: "Cannot play back the audio stream: no audio hardware is available, or the hardware is not responding." When I opened an audio scheme, I got this message: "Windows cannot play the sound %SystemRoot%\media\Windows XP Error.wag. Your sound card may be in use".
What can I do?
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I tried to remove the audio driver and reinstalled it(the WinXp driver) but it also didn't work. My Sound driver is: CMI8738/C3DX PCI Audio Device. The manufacturer is C-media. Website is: www.cmedia.com.tw/
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One helpful info is that: in my Modem Properties box, under "location:", I see: PCI bus 0, device 12, function 1.
While in my Audio Device Properties, under "location:", I see:
PCI bus 0, device 12, function 0. Is it because both device use same bus(0) and device(12) and since, the sound card was installed after the modem that it couldn't work. That's my suggestion, what's yours?
THanks so much.
Johnnny
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If you need more info, please give me your email I will give you more details if you like.

 

I've seen this a few times, & also seen a few supposed fixes ...... I personally have repaired this twice .... by reinstalling the sound driver for the actual motherboard (eg Abit/ ASUS etc).... but in both cases, they were onboard sound cards?????

 

no can do as the sound chip is onboard & no cd was supplied with the motherboard. Although i have downloaded the relevant driver for the Abit motherboard & reinstalled.