Upgraded to 9800GT. Now sound doesn't work.

Problem description: I upgraded from a 7800GTX to a 9800GT today, and now my sound doesn't work. I use onboard sound, and it was fine with the 7800GTX. However, once I uninstalled the video drivers for the 7800GTX and installed the drivers for the 9800GT, my sound stopped working. Four things are listed with a yellow question mark in my Device Manager now that I've never seen before:
Multimedia Audio Controller
Other PCI Bridge Device
PCI Memory Controller
SM Bus Controller

Also, when I go to "Sounds and Audio Devices," it says "No Audio Device" at the top.
Edit: another thing I should add is that these problems occur even when I have no video driver installed.

Attempted fixes: I reinstalled the video drivers, to no avail. Checked the BIOS to see if my onboard was disabled--it's set to "Auto" with the only other option being "Disabled." Googled a shitload and now I have a headache.

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Operating system: Windows XP Pro

System specs:
BFG 9800GTX
ASUS A8N SLI-Deluxe motherboard
AMD 4400+ Dual Core CPU
Onboard sound
(I think that's everything that would actually matter when dealing with this problem)

I have Googled and read the FAQ: Yes

NOTE: I am no good with computers so if there's a driver I need to download please try to give me direct links

 

I did a little of looking around and you will need to reinstall the sound drivers, which are here http://www.majorgeeks.com/Realtek_High_Definition_Audio_for_2KXP03_d4902.html I also noticed that your chipset is a nVidia nForce 4 and those drivers are here. That should take care of those 4 items in your device manager. http://www.majorgeeks.com/NVIDIA_nForce_Unified_Driver_Windows_2000XP_d4299.html Actually, when you installed that new vid card, you didn't have to reinstall the drivers (unless you uninstalled them when you took out the old card) because they would have been compatible with the newer card. Hope that helps! Let us know how it goes

 

That fixed everything but Multimedia Audio Controller Still no sound, but 3 Yellow ?s have disappeared!

 

There ya go.

 

Not quite I still cannot hear anything.

 

Any idea what's going on? Now the Multimedia Audio Controller has a yellow exclamation point.

 

So the HD Realtek driver posted above didn't solve your issue?:confused You still have an error in device manager?

EDIT: I just saw your latest post.

 

I actually just fixed my problem. I had to download the standard Realtek drivers

 

Interesting, I would have thought that the HD drivers were backwards compatible and I guess they're not. I learn something new everyday. That's good to know as I'm bringing my X2 A8N-E out of storage.

 

Glad to hear you got everything up and running again! Sorry about the sound drivers, but like Augie, I thought that the HD drivers also were backward compatible. Obviously they're not:-o See Halflife, you came here looking for assistance and ended up helping us as well!!:-D