Realtek Onboard Audio Problems

Today, I got an ATI Radeon 4760 graphics card. I installed the catalyst drivers, then updated them to their latest version. My GPU has an hdmi port, and the version of catalyst I installed has an HDMI sound driver.

The problem is this:

I have onboard 5.1 audio, and speakers to match. The audio uses realtek high definition sound drivers, and I had previously changed the sound settings with the Realtek audio manager. Upon installing the new catalyst drivers, however, the realtek drivers were overwritten, the manager disappeared, I have no audio, and my speakers no longer function under their previous profile. Their profile in the sound menu, 'speakers', has been replaced by some weird, stereo-only capable something, which still produces no sound. Every install of new drivers only fails, and ends up reinstalling the old drivers somehow. If I try to install through windows default driver search, I get a [code 10] failure. The driver is installed, but is unable to start.

I've been through a number of threads, and invested about 6 hours of my time into this problem. I had viewed a helpful thread on these very forums, which can be seen here:
http://forums.majorgeeks.com/showthread.php?t=148318, if you prefer.

I've done just about every single method I've seen, to no avail. The methods are listed:
1. Deleting all sound drivers and devices in the Device manager. They usually end up replacing themselves when I restart.
2. Uninstalling and reinstalling multiple versions of realtek drivers, in multiple ways.
3. Updating my chipset from the intel website.
4. Run several registry cleaners several times, consecutively, after uninstalling all realtek and windows drivers.
5. Uninstalling and deleting the realtek folder in program files, then reinstalling.

Here are my specifications:
Vista Home Premium SP1
HP Media Center PC m7250n
1GB 200Mhz DDR2 RAM (400 effective, O.C. 214)
1GB 333Mhz DDR2 RAM (667 effective, O.C.)
Pentium D 820 O.C. (from 2.8Ghz to 3.0)
400W Rosewill Power Supply
Radeon HD 4670 256MB DDR4
Motherboard ID: 09/12/2005-LakePort-P5LP-LE-00


I also removed a few pci cards that were in it (TV tuner, Dial Up Modem, old ati radeon x300 GPU)

If anyone can help, I would very much appreciate it. You can also contact me here: not[at]adventuresofjoel[dot]com