Hi,
Without "special" passwords, simply trying to configure your router:
Can you access to the tab "administration" then "firmware upgrade"?
I repeat that question again, cause you didn't answer to me, and if you can't (access to this tab) you won't be able to upgrade your router.
As described here...
Have you been exploring this KB? You may find some test to run to know what's going wrong.
You can also test that (I don't think it will change something, but who doesn't try...):
Copy you real Ip you'll find on that page, then paste it in your browser (instead of 192.168.1.1).
I go to sleep, I'm exhausted.
See you tomorrow.
Ps: Try to describe exactly what you see, what you can do and what you can't.
And if you could explain me again, how that was running before you got problems, and what happened...