iGuRu.gr reader Christoforos Androglou presents us with a Windows bug that allows the time restriction that can be set by the parental control service to be bypassed. 
Let's see how it's done:
When the user's time expires, Windows throws a blue screen asking for an administrator password, in order to give additional time.
From this point, select restart or shutdown and just before the screen closes (it will still say that it is shutting down/restarting) press the 3-key combination ctrl-alt-del together to open the task manager.
There is a timing issue here somewhere, as Christoforos mentions, as it takes about 1 second to complete the exit. Sometimes it opens directly to the desktop, but other times you have to start it from RUN by following the path File – Run new task. Type explorer and press enter.
Privileges and access level are dependent on the user's access levels (admin or regular user).
Watch the video that Christoforos created for iGuRu.gr
https://www.youtube.com/watch?v=PFoTI6PgGug
