Looks like I found a solution. Just posting it here in case it helps someone else.
After looking at other threads there were suggestions that windows movie maker can help but it was not available anymore. I just decided to look in the Microsoft Store to double check and managed to find it and download it (free). There is an option to
rotate videos there but I couldn't see my files (.mpg3 files) to select to rotate them. So I decided to convert a file to mp4 (there is a free downloadable converter through the Microsoft Store too) and after it was converted the video was no longer sideways
and plays properly.
So if you are stuck, try converting your video to mp4 and that may fix the rotation problem. If it is already an .mp4 file try the Windows Movie Maker app to rotate.