Radeon 4850 conflict with sound

[cdn_guy81]

I have this computer :

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01048277&lc=en&dlc=en&cc=us&lang=en&product=3436818

The link will show all the specs, and it came with Windows Vista.  I formatted my hard drive and installed Windows XP and installed Service Pack 2.  I purchased a new 650 Watt power supply and a new Ati Radeon 4850 video card.  The problem is that when I insert the ATI Radeon into the PC, and boot up the computer, I have no sound. 

I have tried un-installing, and re-installing the sound card drivers, however nothing works.  The only thing that seems to work is to remove the ATI card completely, and the sound works fine just using onboard video.

I'm not sure what to do, can anyone help?

[scuzzy]

Put the new video card back in, then download and install the latest drivers for both the card and the audio. The latter is available through the same link that you provided.

It is also possible that HP has issued a fix for this in terms of a BIOS update. But before flashing the BIOS, which can be risky, check your BIOS settings with the new card installed to see if there's a simple adjustment.

[Chandler]

Does the sound card not work at all (i.e. displays an error in Device Manager and/or disappears from Device Manager) or do you just have no sound?  If the latter, check that the sound card is set to be default, because those Radeon HD graphics cards will install a sound device for HDMI audio and perhaps it is being set as default.