Hi, sorry I failed to comprehend you cannot access powershell, so no joy running that cmd.
I suppose a system restore also fails, have you tried this? How long has this been a problem, if restore fails then maybe restoring the registry from regback will work.
Win 10 takes a registry backup every 7-10 days, this can be restored. You need to access the RE, (recovery environment) troubleshoot , then advanced , then command prompt, which you indicate you can do:-
Once into the RE selecting command prompt, we need to establish what drive the RE has assigned the OS, (in the RE the OS is often given another drive letter, we need to know this for our cmd’s to work) you will see a X:\sources prompt, default is X:\Windows\System32> at this we type :-
Bcdedit | find “osdevice” (type exactly as you see here, spaces and syntax important, the | is called a pipe and can be found above the \ key)
This cmd will return:- osdevice…..partition X (where X is a drive letter, we use this letter in the following cmd’s, often in windows ten this is the D drive, you use what the cmd returns, our example use’s D)
At the X:\Windows\System32> prompt type:-
D: (press enter) the prompt now looks like:-
At this type:-
cd d:\windows\system32\config\regback (press enter), the prompt changes to this directory.
Next type:- Dir (press enter)
The contents of the regback folder will appear. Make sure there is data in the folder (not 0 bytes) and check the creation date, if it was before your problem, proceed, if not exit out, it won't work.
If you proceed then next type:-
copy *.* d:\windows\system32\config (press enter)
Type:- ALL to the override prompt, it will say files copied, 5 hives will be copied. Exit out and restart computer.