Did your friend also provide you with the unique 25 digit MS product key.
Having a cracked version of Windows would go some way to explaining why you are having trouble with repairing the OS, illegal software has had important files removed and this would trip SFC up when it was being run.
If the disk is illegal then we cannot continue until you have a legitimate disk/ISO/USB thumbdrive download and appropriate product key, we can help you obtain a legitimate OS by way of download, you only need to have the required key.
From the GTG Terms of Use;
p. The posting of links or references to warez or any other type of illegal software is strictly forbidden. By doing so you risk having your user account terminated without warning. We will NOT help anyone we suspect of having obtained their software or services illegally.