I'm not sure what may have caused it. Did you run any type of cleaning or registry repair type of program before this happened?
I attached the Control Panel shortcut from my system in a ZIP file below. After downloading the ZIP:
Extract (drag & drop) Control Panel shortcut to your desktop.
Unblock the shortcut.
Move the shortcut into the hidden system folder below.
You may or may not have to log off or log in afterwards, but hopefully that'll add it back.
Hope this helps.