Explorer.exe class not registered?

Ive had this erorr and have tried to follow the steps to fix it in other threads but none of them have worked. Ive tried to run the DISM/ System File Checker and it hasnt opened. I also tried to repair the DLL in CMD however CMD wouldnt open at all (neither did DISM). Then I tried to do the next step and make a new account however I couldnt do that either as clicking it and pressing enter didnt work. What should I do?