Hi,
Thank you for your response.
To isolate the issue, we need some information.
1. Have you performed system restore and you are not getting this option?
2. Did you check the issue in safe mode?
I would suggest you to check the issue in safe mode and get back to us with the status.
This issue could happen if the current user account has been corrupted. To check, create a new user account and see if run as administrator option is there.
Hope it helps.