Realtek Audio HD Driver is not working

You've done everything to get it back, except a complete reinstall and that is not something I like to suggest.

Try resetting the BIOS and see if helps. Since you have a desktop, with the PC powered off, open the case, remove the CR2032 CMOS (BIOS) backup battery for at least 10 minutes. Replace the battery, observing polarity and then power on and see what happens. If there were any customization in the BIOS you will have to reset that.

Jack (fireberd) is tops with audio, I'm just jumping in to suggest HP centric trouble shooting pages.

No Sound from the Speakers or Headphones (Windows 7) Compaq Presario CQ5621F Desktop PC | HP® Support

Error in Windows 7: No Audio Output Device is installed Compaq Presario CQ5621F Desktop PC | HP® Support

You've already done some of the steps in the troubleshooting pages above. There might be a nugget of information that might help.

You should also check that Windows Audio and Windows Audio Endpoint builder services are started. I think the mixer dialog will prompt you to restart them if they are not started.

The Event log summary might also clue you in to service issues (error or warning)

Back to fireberd ... good luck

There is either a hardware problem or a Windows problem. If the RealTek drivers are not working, in almost all cases Windows would install the generic "High Definition Audio Controller (Codec) and that would give you basic sound. That apparently not happening.

Did you reset the BIOS - removing the CMOS back up battery as suggested? If the BIOS is not recognizing or not properly recognizing the Sound Chip, Windows will not see it.

If its not the BIOS (or actual hardware) then a Windows corruption is the next thing - and on a "clean" install (reformat the hard drive), and before RealTek is installed, Windows will install the HD Audio Controller, during install, providing its not hardware.

From what I see on the HP site, this Compaq originally had Vista, but Vista/Win 7 are basically the same. Windows 7 is basically "Vista Improved".

fireberd said:

Disable the Microsoft Life Cam and then see if that makes any difference. Some Cams have been known to interfere with PC sound.

You may have to force a reinstall of the RealTek after disabling the cam. In the Device Manager, RIGHT click on the RealTek entry to highlight it and then LEFT click "Uninstall". DO NOT uninstall the drivers. Restart the PC and see if Windows detects the sound and reinstalls it.

@fireberd: I think it might be time to roll the audio all the way back to the base audio. In this post you said DO NOT uninstall the drivers - it might be time to remove the software when uninstalling so that Windows finds the device and installs the base driver.

@Antonio: Have you tried headphones - that would eliminate speakers being bad, off or low volume.

I had an HP that developed a few device problems (no audio and no DVD) - a reinstall solved the issues for a while, but they came back. I was able to solve the audio issue, but I can't recall the resolution. Too many attempts with drivers and configurations and it was a long time ago.

Fix: "This device cannot start" Code 10 error in Device Manager in Windows
I don't know your comfort level with the registry Antonio, but the KB article above reminded me of other things I attempted way back when.

I would hold off on any manual registry changes until you've eliminated all other solutions.
The uninstall - roll back to base driver might do the trick.

AntonioC said:

I have done most of the steps outlined in the HP page and none of them seemed to work for me. Also, when I try to troubleshoot the problem, it says there is a problem with audio driver and when I apply the reinstall fix, it gives me the error that it failed.

Most of the steps?
--> Try all of the steps.

Troubleshooting - what was the exact information ... was it simply there is a problem with audio driver or was there more information?

Reinstall the fix?
Error that it failed?

You'll need to be more specific - members can't see what you see.

What was the fix you tried? Reinstalling the driver?
What was the error code and exact message.

You can post screen shots of any error dialog boxes.
See: Screenshots and Files - Upload and Post in Seven Forums

Thanks

My take, from what the user has posted. Windows is not seeing the sound hardware. Three things can cause this (1) the BIOS is not detecting it (and if the BIOS is not detecting it then Windows will not detect it). (2) There is a hardware problem with the Device (3) A Windows Corruption (or not installed properly).

Jack