i just successfully converted an HP Pavilion 7955 that came with XP to ME. The conversion went simple til i got to sound drivers for the Intel 82801BA/BAM AC'97 codec. It took some net searching and several attempts but I have finally got the sound working. The HP motherboard is an Asus P4U-LA but this won't help since its not listed on their website. I did however discover that Compaq uses the same motherboard and a review of the Compaq website resulted in a solution that worked for the HP Pavilion.
1. Go to the Compaq website and download the audio driver patch for the Soundmax Integrated Digital Audio system. it will be large ~25M
2. Run the self-executible file that you download "sp19611.exe" which will load the file in \COMPAQ\diretory.
3. Run the setup and answer questions as asked.
----the following steps load the drivers---
4. Open Control Panel ->System->Devices
5. Locate the Sound entry that will read something like "Intel 82801BA/BAM AC'97"
6. Either delete this device or open its properties.
7a If delete-> refresh; point toward the Compaq directory: \compaq\sp19611\smaxwdm
7b.If select properties, then make the following selections:
->driver update->specify the location->specify location->browse to point to the \compaq\sp19611\smaxwdm directory
8. Select the folder "SE" for 98SE/ME or "W2k" for 2000.
9. After the drivers load and the PC restarts the Sound driver will now be displayed as "SoundMAX Integrated Digital Audio" and should operate as it should have the first time.

Good luck