C501NR Device 27D8 HD Audio Drivers

As of this writing, there are three letter versions (A, B, C) and multiple sub-versions of the UAA drivers. Two generic installations can be found on support.intel.com by searching for UAA. The larger file, UAA.ZIP, is a multi-language installer. The smaller file is for USA only. Searching www.hp.com for "UAA" returns a number of UAA articles and SoftPaqs. The Microsoft knowledge base details file versions and dates for the most current files.

The UAA installer is stupid. It does not remove previous or failed installations, nor does it repair an installation. It just runs, says everything is fine, and you can still have a broken "High Definition Audio Controller" entry in the Device Manager | System Devices section. The trick is finding and deleting all normal and hidden HD files from the Windows directories before running the UAA installer. The UAA package will then install and the High Definition Audio Controller will no longer be broken. These are the files used for XP Pro / SP2:

• Hdaprop.dll
• Hdashcut.exe
• Hdaudbus.sys
• Hdaudio.sys
• Hdaudres.dll
• Portcls.sys

UAA must be installed before Sound and Modem drivers.

After finding a combination that worked, I restored the virgin machine from a Ghost image and did it this way:

SP32395, Compaq UAA v1.00C
SP35270, Conexant HD Audio
SP35272, Conexant HD Modem

ftp://ftp.hp.com/pub/softpaq/

These three files provide a no-warnings installation of HD Audio using the standard XP Pro / SP2 cdrom.

The first thing is to identify the chip. Open the Device Manager, and check the Details tab. This will give you a lot of numbers:

VEN_xxxx, DEV_xxxx

Check them out on: http://www.pcidatabase.com/ to find out if anybody knows what it is.

Once you have a clue, download the drivers you think might work. Open the INF file and search for the VEN and DEV match. If not in the INF, those drivers won't work.

It is always easier to do it before hand. If the system is already up and running, Windows can identify the chip in the Device Manager | Details property.

Another reason is, if this is your only machine, be SURE to get the correct network drivers before you blow it away. If it requires a special network driver, and it is not built into WinXP, you will need another means of downloading it from the internet.

I *always* GHOST the existing disk image before making changes. If you don't do this, you will have no safety net, and no way to return to the previous state, should things fail.