Only administrators can make other administrator accounts.
The account that handel all others guest or normal accounts.
how can i log in on administrator account so that i can download games in my loptop?
You can't that is the reason for the restriction. You could wipe out the entire OS and reload is as adminstrator but that will only give you access to that particular computer. There are ways to go...
You need to be the Root (First admin) to do that.