That's an install disk then.
The System Restore option is to restore to a prior time when the computer was working fine.
Normally you would also get an option to restore with s system image you had created earlier, but I don't see that in what you have listed
I'm not sure what the separate Repair option does unless that takes you to the Recovery Environment where you can use either of the other options you have listed.
If the latter is the case, which option did you use ?
It would be a hell of a coincidence if your audio device had given up the ghost following a repair, so I'd still favour a driver problem.
As you have already downloaded the driver for it, perhaps it would be best if you contacted Medion.
https://www.medion.com/gb/service/contact/
There's something else you can check though.
In All Control Panel Items click on Sound and then on your Realtek and select Properties.
You may find another Properties button to click on and then you can check if it is enabled.
I used the system restore option because I had got it accepting manual restore points shortly before that
but they were not holding for any length.
The present problem with the Windows updates seems to be caused, in part anyway, by not being able to
create restore points.
In the Properties section in Device Manager under General it says No Drivers Are Installed For This Device.
Under Driver it gives an install date of 13 10 2015and gives a long list of driver details.
Under Update Driver it says that the best driver for this computer is already installed and up to date.
Under details it says Value Realtek High Definition Audio.
There was no other mention of Properties.
Strange that one heading says No Drivers installed and another says Best Driver is installed and up to date.
Have never had a problem with audio but it is only following the repair.