Installed latest Windows update but after all there is no sound

I have just installed the latest Windows 10 update Version 10.0.17134 Build 17134
But after all there is no sound. Before Windows update I had sound with Realtek High definition driver.
Now I don't. There is red X sign next to sound icon at quick launch bar.

And in troubleshooter it shows inadequate information. It also says my audio output is plugged out but it's not.
I don't know what to do.

Before windows update I have specifically created system restore point.

If I won't be able to solve this then I'll restore. But maybe I'm doing something wrong.
At device manager it says I have appropriate audio driver. But why the hell it doesn't work?

Long ago I did specifically smth deep inside special options that with each update it wouldn't touch my audio devices. But it touched. I don't remember where and what I did. But it is related and written in my last post here. Though I should find it. I doubt whether I;m correct.

HelP me.

Damn it. In past I created system restore points. Now that I'm browsing through System properties it says I haven't created any restore points. What an injustice!!

I don't know whether it is latest for real. I'm suppoesed to think like that. If W10 wanted to update it means it got smth new. I don't know how it happened that it actually installed old update.

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Tell me what to do to enable sound. It's terrible.

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dalchina said:

If you upgraded to a new build, restore points from an older build are completely irrelevant and are deleted by design. And of course they won't be there if you did a clean install.

I haven't reinstalled whole Windows from boot CD. So I suppose it's not "clean install". I don't know how to understand "clean install".
It was just an update that lasted about 20 minutes. Screen was light blue with growing percentage.

Thank you for your attempts to help bro67 and dalchina. I just reverted back to previous built: Version 10.0.16299 Build 16299
Now I have sound again. It's really strange that with Windows updates and its new builds my system loses sound. I don't know why. I would do what you asked bro67, but I will have to update 20 minutes again just to do all your actions you mentioned. It's a miracle that the system can reverted to previous builds. Honestly I always though that there is only such thing like "System Restore". But , Jesus Christ, there is something completely different - System Recovery. I opened control panel, went to "Update & Sucurity", the n on the left column "Recovery" and there was this "revert" or smth, - I already forgot how it was called. But this is smth with which I'm really satisfied.
Guys, if there will be the possibility to "System Restore" or to "Revert to previous build" then later I will update and if I will not have sound again, I'll try to find what is wrong. I think I'll do this later.