vista Ultimate and Audio

Hi there, I need some help with audio drivers.

PC Stats:
OS - Vista Ultiamate x64
Mobo - ASUS M3N78 Pro
CPU - AMD Black Edition Quad-Core


I have a clean install of Vista Ultimate on my PC and I am not able to get my sound drivers to work.. I am trying to install the drivers for Realtek HD Sounds. sofar here is what I did...

*Installed correct Drivers - no go - says i have a signature error
*Allowed Code Signing for Device Drivers. Its set to prompt
*ran pnputil to install and add drivers Heres my error on that.
C:\Windows\system32>pnputil -i -a D:\Drivers\Audio\driver\Vista64\*.inf
Microsoft PnP Utility

Processing inf : HDX861A.inf
Successfully installed the driver on a device on the system.
Driver package added successfully.
Published name : oem8.inf

Processing inf : HDXCPC.inf
Successfully installed the driver on a device on the system.
Driver package added successfully.
Published name : oem9.inf

Processing inf : HDXHPNB.INF
Successfully installed the driver on a device on the system.
Driver package added successfully.
Published name : oem10.inf

Processing inf : HDXLC.inf
Successfully installed the driver on a device on the system.
Driver package added successfully.
Published name : oem11.inf

Processing inf : HDXLC2.inf
Successfully installed the driver on a device on the system.
Driver package added successfully.
Published name : oem12.inf

Processing inf : HDXRT.inf
Failed to install the driver on any of the devices on the system : One or more a
rguments are invalid
Adding at least one driver package failed!

C:\Windows\system32>

Anyone got anymore suggestoins?