left shift key makes these characters: zcvx,m?>

[Lilavati]

I am using an HP 625 laptop, with Windows 10 Pro, version 10.0.19041 Build 19041. 

A few weeks ago both my shift keys started making problems, when is press the left shift key once, then these characters appear: ycvx,m_: when I use the German keyboard, and zcvx,m?>  when I use the English keyboard. simultaneously it makes a few beeping sounds, and sometimes it reduces the speaker volume or mutes the speaker.

when I press the right Shift key while using the German keyboard, it makes these characters: qerwiuPO, simultaneously it makes a few beeping sounds and selects a line of text. when I use the English keyboard, it makes the same thing, also it sometimes reduces the sound volume. 

I already searched in some forums and tried to solve the problem by trying different things: I updated Windows, I updated, rolled back and again updated the keyboard driver. I used the Ccleaner to clean the laptop and repair registry faults. I ran Malwarebytes, updated and ran Spywareblaster and Avast Free Antivirus. I uninstalled all language packs and keyboard except English US, but since that also did'nt solve the problem, I use the German keyboard again, because otherwise I have difficulty finding the special characters. I ran SFC and DISM. After completing everything, still the problem with the shift key is persisiting. I cannot do more complicated things without guidance, thus I request you to assist me how to solve this problem.