You don't have permission to Shutdown this computer, wait what?
Windows 7 users were never left alone, even after their support from Microsoft ended. Lot of Windows 7 users has now reported that they are no longer able to shutdown their Windows 7 PC. Even when they decided to do that, they will get the above pop-up "you don't have permission to shutdown this computer". If you are the one who is facing this issue, then i hope the following solution that might work for you.
Solution 1: Try disabling services.
1) Press Windows(logo) key and R keys Simultaneously.
2) Type msconfig and Hit enter
3) In the window that appears, Check the box "Hide Microsoft Services"
4) Once you did that, Now select Disable All option
5) Log off and login again.
You can see the issue to be fixed.
Solution 2: Try Group Policy.
It works only on all editions like Windows 7 pro, Enterprise,etc except Home
1) Press Windows (logo) Key and R keys.
2) In the run command, type gpedit.MSC
3) Navigate to C
USER ACCOUNT CONTROL: RUN ALL ADMINISTRATORS IN ADMIN APPROVAL Mode"
5) Double click to open, In the window that opens, select "Enabled"
6) Click Ok.
Now, again Press Windows (logo) + R Keys to get run command.
7) Type gpupdate /force and Hit Enter key.
Now try again, it will work.
If Everything fails, then Solution 3 will work.
Press Ctrl+ Alt + Del Keys, in the right corner there will be Power button, click on it and Shut down.
-Hope it is helpful :)