Finally. Simple parental controls for Windows

Install AutoLogout on a Windows account to create a simple, time limited, session
Once AutoLogout is installed, a timer appears in the bottom right corner of the screen, counting down remaining screen time. When 10 minutes remain, a sound will play. When time is up, the user will either be logged out or the computer will shut down (depending on bedtime).

Control screentime, bedtime, and monitor usage with the control panel
The control panel is password protected, by a password you enter during first-time setup. Settings can be adjusted here, or you can link your phone with a QR code and control settings remotely for your convenience.

Remote control and monitoring with the AutoLogout Manager app
The AutoLogout Manager mobile app gives you all the same controls from the control panel, but with the added convenience of being able to change settings and view usage while the computer is off.
More about AutoLogout Manager