I've seen many solutions in this problem but in my state, as a 14-year old boy I wanted to repair my computer myself.
This is my case:
My Administrator account is suffering this kind of error while today I am using a guest account / standard user.
How can I fix the error without administrator privileges.
Plot Twist : I don't know the administrator password, if I do I can fix this error months ago.
Can somebody tell that I really need computer repair people to fix my computer?

Boot to safe mode and run a system restore.

I've tried that before but it did nothing.