No audio device installed

[8ch-DeeFan]

After installing (and eventually uninstalling) SP1 for Vista, I get no sound.
If I click on the Volume Mixer icon it says "no audio device installed". However, all the indicators in the Device Manager say it is working. I have uninstalled and reinstalled virtually every Realtek driver available for Vista and HP. I have checked in BIOS and set the on-board audio to "enable", but still no sound.

Before I go insane, does anyone have any suggestions?

 

[raybay]

Remove or disable the driver in the Device Manager, then download and install the latest driver. If that doesn't work, go back to the next previous driver.

 

[8ch-DeeFan]

Remove or disable the driver in the Device Manager, then download and install the latest driver. If that doesn't work, go back to the next previous driver.

Ok, I removed the current Realtek hd audio driver (version 1.90) and then Vista auto-loaded an audio driver from Microsoft I had never seen before. Should I remove this driver as well and then reload the latest driver?