To answer the question how to block it, here is the simplest way:
go to internet properties,click the content bar on the top,by the content advisor click settings. mark the box which says “supervisor can type….” then click onthe password box underneath to activate a password of ypur choice.
You need to click on the ratings top left of the same window to put the slider to the left and the word “none” will come up. then you will be able to enable or disable the internet just by going on the internet properties and content adviser in contents to block the use iof internet. hope this is useful.