Black screen but audio still play

The K-lite codec pack just have the issues - black screen while the audio playing after I upgrade my window 10 ver 1709 to ver 1809. Please help me.

Updating your graphics driver usually fixes that problem.

I have upgraded graphic, reinstall, but none of them working

Start > K-Lite > LAV Video Decoder > set "hardware decoder" to "none"

If that does not help, then try different video renderer:
MPC-HC options > Playback > Output > DirectShow video

These are just workarounds. It is caused by a driver issue, so there isn't anything else I can do to help.

I have the same problem, that the screen in MPC-HC remains black whilst audio is playing.

However, in MPC-HC options > Playback > Output there is no option for "DirectShow video". However, when changing the settings there to "System-Standard" then the video shows.

BTW: the driver for the praphic card is up to date (AMD  Mobility Radeon HD 5000 Series, version 15.201.1151.1008, date 04.11.2015).

Did you try disabling hardware acceleration in the the video decoder settings? That will probably also solve it.

I have seen several cases before where hardware acceleration wasn't working properly on mobile AMD GPUs.

K-Lite Mega Codec pack 15.2.0
Hardware Acceleration

Settings for MPC-HC:
Decoding Method: Use software decoding

Settings for other DirectShow applications:
Decoding Method: Use software decoding

Detected GPU:
AMD Mobility Radeon HD 5000 Series (1024 MB)
Vendor ID: 1002, DeviceID: 68c1
Driver: aticfx64.dll (Version 15.201.1151.1008) (11-4-2015)

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I did these settings during the installation process of K-Lite Mega Codec pack:

--->  The screen of MPC-HC remains black.

In that case the only solution is to change the video renderer.

Maybe this helps:
https://www.youtube.com/watch?v=aXCPj1yyj9E

Thank you very much.
Changing the AMD laptop energy settings as shown in the youtube-tutorial unfortunately also did not fix the black screen in MPC-HC. Thank you for the hint.
How would the "video renderer" be changed?

You already did it before:
MPC-HC options > Playback > Output