Rendering makes trouble with sound and quality

Thank for all the answers. Unfortunately the problem is still the same. But i've tried to consult my son in law, who uses premiere pro and there were no problems with the same files.  He's got 24 MB Ram, I've got 16 MB maybe thats why.

I'm not sure you need it for this issue, but you said you couldn't get VLC from the Microsoft store.  Try downloading VLC from the source:  https://www.videolan.org/vlc/

Changing extention is done in windows explorer in the same way you change a file name.

dsc_001.mov > dsc_001.mpg

I'm sorry my skills are not to convert .MOV to MPG. I've tried to download VLC app in the Microsoft store, but it seems like a wrong version. At least i could'nt change anything. What about what Steve wrote about version? Do I have to find someone who has Premiere Pro (newest version) or can iI upgrade my 4 month old  Premiere Elements to get it to work?

Could try to change the extension from mov to mpg. See if that will work.

Oooops your'e right. The file was from my Canon EOS 5D.  I've tried to rename the file to DSC_1000.MOV put it in again, rotate it and render, but the problem is  still the same.  It seems that my Nikon D7100 moviefiles works, but they still get more pixelated after 180 degree rotation and rendering

Your clip info in not of a Nikon, but anyway those camera's make constant framerate.

Delete the clip from the project, rename the clip and import and drop it on the timeline again, rotate.

See how that goes.

This often happens in pre-2020 versions of the program when you use video that has a variable frame rate.

Open one of the videos from your Nikon in the free download MediaInfo. In MediaInfo, set the View to Tree and then copy the report that is generated and paste it to this forum. Once we see what your video is composed of we'll better be able to advise you.