Disclaimer: I don't use Parental Controls so this is just a guess.
I believe that Parental Controls is a part of the Family Safety app in Windows Essentials. Windows Essentials - Microsoft Windows
Under the old Windows Live (which I believe was replaced by Windows Essentials) it was possible to go into control panel > programs and features and uninstall individual components. You could see if this is still possible with Windows Essentials*
. Uninstall the Family Safety app and then reinstall. It's possible that the app may have become damaged or corrupt and a fresh install may cure what ails it. *
In Windows Live there was a plus sign (+) in front of the main app. Clicking on the + would expand the app and reveal the individual components.
If this problem just recently started, you could also try rolling back your computer to an earlier date/time using System Restore. System Restore