Hi,
My name is Igor, it's a pleasure for me to help others and I'll try to help you.
Sorry, we are just other users answering here neither Microsoft employees nor support persons.
For icacls, go to Recovery environment, run command prompt, check the c: is system volume and run
icacls c:\* /Reset /t /c /l /q
command. If a Windows disk has another letter in this environment, correct the command.
Please note, this command restores original access rights.
For takeown, please run command prompt as administrator and run the command below. Do not miss spaces between options.
takeown /f c:\* /r /d y
Note, you will not take ownership on protected system folders.