Do not erase and re-install the OS. That is very, very unlikely to fix anything, and will just be a lot of work for nothing.
The above posts are a little confusing, but I think you haven't clarified what you are actually trying to do, or expecting to happen.
I don't know when you first used MC, or what versions you have used in the past, but you joined the Forum on March 25, 2018, so I am going to assume that the first version of MC you used was MC24. Also, based on the above, I will assume that you have never had ratings in any version of MC, and so I have to assume that you are trying to get ratings back that you applied using some other software, at some earlier time.
If the above is the case, then maybe the previous software never wrote your ratings to the files, so MC has never been able to find them. Or possibly the ratings were written to the files, but using a non-standard format. MC can't read ratings tags from some other software source unless they have been written to the files in a standard format. For example, MC reads and writes Ratings into the ID3v2.3 "POPM (Rating)" tag for an MP3 files, and to the Vorbis Comment Block "RATING" tag in FLAC files.
Also note that as Rating is a very personal thing, when ripping CDs and getting metadata from online databases, MC doesn't get any Rating values stored in tags, as they wouldn't match your personal Ratings.
So, how far off am I? Am I correct about the above?
If so, what was your previous software, do you still have it and would it still work on your PC?
Did you have ratings in that software, and can it be used to write those ratings to tags in the files, so that MC can read them and update its Library?