That is actually quite strange.
As far as login goes, 192.168.1.1 or 0.1(forget, mine is 2.1 because I just always used that numbering setup)
I think the default is actually no password.
Failing that, the manual has the full instructions for resetting the router to factory defaults. Remember to take down your settings if you use DSL. most other services work with default settings.
Always setup wireless security(if you have wireless) after a reset to keep un-wanted users out