Try this : https://addons.mozilla.org/en-US/firefox/addon/disable-autoplay/

Please let us know if this solved your issue or if need further assistance.

No. Problem still alive.

If it can help, this problem is also on this site: https://www.newegg.com/Product/Product.aspx?Item=N82E16829132072

Microsoft will and does change your drivers in Windows 10 Please put the fix in for all Hardware or just choose the link of the page to figure out just the video card https://www.howtogeek.com/263851/how-to-prevent-windows-from-automatically-updating-specific-drivers/

Ok, do not see on page the error you mentioned. Did find the card, went to Asus and download page. Pick your OS version and reinstall the drivers after have done the above fix. https://www.asus.com/Sound-Cards/Essence_STX_II_71/HelpDesk_Download/

I would also suggest checking in your Bios that the on-board sound card is disabled.

If still have issues : https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows and https://support.mozilla.org/en-US/kb/html5-audio-and-video-firefox

Please let us know if this solved your issue or if need further assistance.

So.. I have done, what you suggested. I prevented Installation of the device and....now I can't install drivers for soundcard:) Neither via setup.exe, nor via Device Manager. Then I canceled fixes, reinstalled drivers and forcibly disabled on-board soundcard. So, It worked! Thanks. But why this problem takes place only whit Firefox? Edge and Chrome works correctly with both soundcards.

No, it started again. Even with disabled on-board audiocard.

Is it possible to find russian support?

You can go to this Russian forum website:

• http://forum.mozilla-russia.org/

Thanks!