Cannot get my sound to work, please help!

I recently upgraded from XP home to windows 7 and everything is running beautifully with the exception of my sound. I cannot get it to work for the life of me and I'm not sure what else to do at this point, so here I am! I upgraded my video card recently to the Radeon HD4650, which comes with HD Audio. I cannot support HD audio so when I was running xp I disabled the audio driver for the video card and was using my on-board sound(Realtek) drivers, which worked fine. Then I upgraded to windows 7 ultimate(64bit) and I'm not getting the drivers to work for me. I've downloaded the Vista and Windows 7 drivers and nothing. I'm not sure if I'm using the correct drivers for my motherboard or not, so here are the specs for it! Any help would be greatly appreciated!
Manufacturer: Asus
Motherboard Name: A8M2N-LA
HP/Compaq motherboard name: NodusM-GL8E

Motherboard Specifications, A8M2N-LA (NodusM) - HP Customer Care (United States - English)

it says :

Onboard audio

* Built-in High Definition 8 channel audio
* ALC883 or ALC888 CODEC

ALC883

ALC888


~~~~~~~~~~~~~~~~
So:

your audio is ALC883 or ALC888

Realtek 8-channel

Realtek Downloads

I clicked all the links and I'm still not seeing anything to download that works.