Play on the administrative account. It might be because you need administrative privileges. Ask your father to make you count a normal one, or do it yourself because you know the admin password… By the way, why are you playing Diner Dash when your 15?

if ur father allows then u can create ur own administrator account from ur father’s account or change ur present account to administrator account,and these can be done from the administrator account only.If ur father doesn’t allow,there are some games while installing it asks whether everyone of this computer can use this or only the adminstrator,so try to uninstall and reinstall the game from ur father’s account and while installing look for the option that i have mentioned.but some these options are inavailable in that case u need change urself as the administrator,there is no other go.
In order to make urself as the admin account go to control panel->user accounts and the instructions will be given there.bye