Windows 10 Home single language doesn't allow any virus guard installations
Windows 10 doesn't allow installations and block them by the "System administrator has blocked this action. Contact your system administrator or log out and log back in as the system administrator." message.
When I logged in from the built-in administrator account, it says "The digital certificate of installation files is invalid"
Which security program? Have you downloaded its latest installer from it official website? You should bring this to the notice of the program's developers.