1. Mount the .ISO file by double clicking on it.
2. Open 'Windows Powershell' or 'Command Prompt' with Admin privileges (right click -> Run as Administrator)
3. Let's check the System Health first, by running these commands:
3.1 dism /online /cleanup-image /scanhealth
3.2 dism /online /cleanup-image /checkhealth
3.3 dism /online /cleanup-image /restorehealth
4. I'm sure that 3.3 will give you an error stating that it could not perform the task. And now it's when the mounted ISO comes into play. Let's specify the file from the ISO so that we can fix it. Run the following command: (Notice that X must be the drive letter on which your system has mounted the ISO)
4.1 DISM /Online /Cleanup-Image /RestoreHealth /source:WIM:X:\Sources\Install.wim:1 /LimitAccess
5. Now let's repair any damage in the system files, shall we?
5.1 sfc /scannow