I am kinda blind as how to fix your computer without looking at it. I cannot give good advice without physically looking at it.
1. Try disk cleanup in settings and also by right clicking on “C” in my computer.
Second suggestion and this is pretty drastic.
In Settings go to Recovery and click on reset this PC.
You will have to reinstall your programs from your disk back up.
Make sure you copy all your documents to a backup drive before doing this.
I tried that but, again, it said I didn't have enough available space to run the reset.