C7000v2

> Model: A7000|Nighthawk AC1900 WiFi USB Adapter - USB 3.0

   Not a router (or a modem+router).

> I can't login

   "can't" is not a useful problem description.  It does not say what
you did.  It does not say what happened when you did it.  As usual,
showing actual actions (commands) with their actual results (error
messages, LED indicators, ...) can be more helpful than vague
descriptions or interpretations.

   Visit http://netgear.com/support , put in your (actual) model number,
and look for Documentation.  Get the User Manual.  Look for "Types of
logins".