Dear fahim mahi,
Hello! Welcome to the Microsoft Community. I'm glad to be able to help you. If I don't understand your question, please let me know immediately.
I understand that you have a problem when using Windows Security Center, you can't enter the system, and it points out that "you are not an administrator". I understand the inconvenience caused by this problem. I will try my best to help you solve it.
Please try the following method first. If it doesn't work, please tell me, and I will find another method for you immediately.
Go to C:\Windows\System32\SecurityHealth. It it's empty:
- Download SecurityHealthSetup.zip
- Unzip SecurityHealthSetup.exe, then right click and run as administrator
When you finish this, you should return to normal immediately. If not, please restart the computer, let the computer initialize for a few minutes, and then check it again.
This method comes from I'm unable to open windows security app - Microsoft Community
I hope the above information can be helpful to you. If you try the solution, feel free to tell me the results or the problems you encounter.
Best wishes
Pyked | Microsoft Community Support Specialist