Sorry its Alienware 15 R3

Hello Crimson,

For solution 1, I had already uninstall the Realtek audio driver, and also I try to press the "scan for hardware change" in the device manage, however the window did not help to reinstall again.

For solution 2, the driver booster state that my "sound, video and game controllers" are already up to date.

For solution 3, add legacy hardware in device manager, so I try it but it shows this 

For solution 4, my system device doesn't have the "Microsoft UAA Bus Driver for High Definition Audio" to be disable/uninstall.

Are there any more alternative ways that I can try to solve the audio driver problem? Thank you.

Hi @Yang0512 welcome to this free user to user Alienware laptop discussion forum. This is not Dell Support. 

Solutions to this Alienware 15 R3, Realtek Error code 0x00000002 problem are included in [Solved] Install Realtek HD Audio Driver Failure on Windows 10 (tencomputer.com). One of their four solutions should fix this problem. Please share an update. Thank you. 

[This user does not work for Dell and volunteers their free time. Please remember to say thank you by clicking on Kudos as this user's only reward.] 

My audio input/output had disappear because I uninstalled it and also the "sound, video, and game controllers" which shown as above. 

Hi @Yang0512  thank you for sharing additional information complete with images.

Please excuse asking for clarification why the "sound, video, and game controllers" were uninstalled, and if they have now been reinstalled? Thank you. 

Hi, sorry for the late reply, the image taken below is from others PC's device manager which had "Audio inputs and outputs" in it. 

However for my case as shown below,

because I uninstalled it to reinstall the latest audio driver. So my "Audio inputs and outputs" had been disappear. So I had some problem with that because my audio had a red cross beside it as shown below,

If it clarify my problems, thank you very much for helping.

Hi, Crimson

I clicked the audio icon, and its troubleshooting and the result is shown below,

which means that I simply doesn't had any audio input/output downloaded, which means I need to download the Realtek audio driver. Thank you.

Hi @Yang0512 thank you for sharing additional information complete with images. 

Your Device Manager does not have any yellow warning triangles against any drivers. There is no group of drivers moved to the right saying that they want attention. As all your drivers are good, and taskbar audio has a red cross, please click on audio icon to switch the audio on. It will either activate audio or give error message to reveal problem, so that it can be fixed. Thank you. 

Hi @Yang0512 thank you for sharing what happens when taskbar audio icon is switched on. 

Alienware 15 R3 Drivers & Downloads has Realtek Audio Driver Version 6.0.8816.1, A09 and option to install Older Versions. 

In your opening post, Realtek Audio Driver Version 6.0.8816.1, A09 failed to install. Please install Older version that is known to work, if you can recall its version.

Alternatively, install the original audio version that was installed when your Alienware 15 R3 was delivered from factory (12 Jan 2017). Then, if an application needs a more recent version, it will create message to update to version that it wants.

General advice: Do not install Dell update, just because there is a new version. 

Please share your fix that works. Thank you.