Router help! dlink DIR-615?

It's so annoying it says on the sticker on the back of my router that to log in as an admin on the router just have admin in the user field, then leave the password field blank, that just doesn't work! I can log in as a user but it doesn't allow you to make the changes I want to make (I want to do port forwarding), I reset the router with the reset button (used a tiny needle) all was good, had to change the security key, then I type in my ip on the browser and when I do admin in the user field and password field blank it is still not working. :( even when I type "Admin" instead of just admin with a lowercase a it doesn't work!