Can't connect to admin, reset hasn't worked

[ToussiaintOps]

My boss handed me a router to connect to from his home office. Trying to repurpose it here in the work office.

I connected the router, a NightHawk X6S R7900P. I logged into routerlogin.net and entered admin and password. It didn't work. So I hit cancel and tried entering the serial number and that didn't work either. I figured maybe his admin password had changed so I did a factory reset by hitting the reset button for 7 seconds while it was powered on and tried again and I still can't connect to admin either in the browser or in the app itself. Even if I make sure I enter the serial number perfectly it says

So I am not sure how to proceed from here. I thought resetting the router would reset the admin/password settings to default. Any advice?

[FURRYe38]

Be sure you clear out the browser caches before entering the routers web page.

Try pressing the rest button for 10-15 seconds in back then release. 

Enter in 192.168.1.1 in to a browser. 

Try MS Edge, IE, Firefox or Opera browser.

[ToussiaintOps]

It is still providing the same error. I cleared the cache for Microsoft Edge and tried that, and it didn't work. I downloaded Firefox and tried that, and it was the same result. I also long reset as you suggested. 

[ToussiaintOps]

I have to wonder...

there is another nighthawk router set up nearby, with admin but a different password. 

Could the presence of a second night hawk router be interrupting the setup of this one by any chance? 

[FURRYe38]

Are you ethernet connected to the router with one PC? Ethernet would best to avoid any wifi confusion.