Hi Joseph.
1
If you are missing the shut down option on on the power button on your start menu, right click your start button, is the shut down option available there?
If not, on your Desktop, press Alt + F4, does that bring up the shut down dialog box?
2
If not, did you install a secure browser like the Respondus Lock Down Browser to take an online exam?
3
If none of those options work to shut your PC down:
Click your Start Button, type regedit and hit Enter to open the Registry Editor.
Click View and make sure 'Address Bar' is turned on.
Paste this into the Address Bar at the top and hit Enter.
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
Please provide a screenshot of that Registry Editor page.