404 Not Found File not found

> [...] when i try to connect ont the web interface to configure it, i
> have an error page with the message :
> 404 Not Found
> File not found.

   "try to connect" how, exactly?  As usual, showing actual actions with
their actual results (error messages, LED indicators, ...) can be more
helpful than vague descriptions or interpretations.

   Are you specifying that exact URL
("http://192.168.0.1/webpages/login.html" -- some old bookmark?), or are
you using a simple "http://192.168.0.1/" (as it's written "under the
modem")?

> [...] but not the 192.168.100.1 beacause i'm not in the same
> network...

   On a DOCSIS cable-tv modem(+router), "192.168.100.1" should always
work, even though the ".100." is on a different subnet.  I wouldn't
expect it to work on a DSL modem+router, however.


> Make sure [you're] connected wired to ADSL modem/router not wireless.
> [...]

   Why should that matter?

> [...]how-to-find-your-routers-ip-address-on-any-computer-[...]

   A 404 error occurs when you're talking to a web server, not when
you've specified some nonexistent IP address.  The question here is
whether "/webpages/login.html" does/should exist on this router's
management web site.  If it existed on this modem+router before the
"factory reset", then I'd expect it still to be there after the settings
reset.

   After a firmware update, many things are possible.  A different
firmware version could have a completely different web-server
directory/file structure, so a particular old URL might fail this way,
but a simple "http://192.168.0.1/"  (or "http://routerlogin.net") should
still work.