I finally found it.
glob@7.2.2 <- This is problem

I haven't looked for it exactly from what point, but it's version 7.2.0 in the package at the point where that package works well, and version 7.2.2 in the "nothing to compile" version.

Type the "npm intstall glob@7.2.0" into an empty project and copy /node_modules/glob
copy /node_modules/glob to YOUR_HARDHAT_PROJECT/node_modules/hardhat/node_modules/glob
It works.