Google the model of the router and you'll find the default login info, if you've forgotten the login info and it's not the default, there is a button usually in a hole on the back of the router, this will reset everything to default and if you don't know the login info for your ISP, you will not have any connection until you input this login info. This info can usually be obtained by calling your ISP, if they don't give you the info, they'll come by and set it up for you.