Let's talk about software installation first. Almost every software needs to store quite a lot of information on disk C when it is installed. Whether you like it or not, the operating system is determined in this way, so the more software is installed, the smaller the capacity of drive C. After redoing, these things are gone, and the C disk is big. The previously installed software needs the support of auxiliary files on drive C, but after redoing, these files are gone and cannot be used. You can delete these softwares.