CUPS Printer Problem with HP G55 on USB

I have an HP G55 hooked to usb port 0. All indications are its OK, but test print says it completed successfully but nothing prints. When I go to localhost:631 and select Admin printers and then try to change configuration it asks for a password and ID I use Root and its password but it tells me it cannot authicate it. Where do I grant authority for this. i am new to Linux and am not sure what needs to be done. Any help will be appriciated.