Not connecting to internet- gateway is invalid

[Harmook]

Hi all.  I have tried to reinstall my DGND3700 N600 Wireless Dual Band ADSL2+ Modem Router after it went offline last week.  My son decided to conduct a factory reset and I have not been able to reconnect to the internet.  I get the following message when I use the Netgear Genie:

Testing the gateway...

The gateway is invalid.

Cannot test the DNS

The router Internet port has no connection or the connection is loose or the .....

It then suggestes rebooting the router which doesn't assist.  

Can anyone shed any light?  I have used the DNS servers recommended by Internode my ISP but that makes no difference.

Thanks to anyon ewho can assist.

[antinode]

> [...] DGND3700 [...]

   Hardware version ("DGND3700[v1]", "DGND3700v2")?  Firmware version?

> [...] I get the following message when I use the Netgear Genie: [...]

   I'd forget the Genie app (running on what, by the way?), and use a
web browser.

> [...] My son decided to conduct a factory reset [...]

   Then I'd guess that you'd need to reconfigure your DSL interface (at
least).  Did anyone save the old/working settings before the disaster?

   What do the LED indicators on the DGND3700 indicate?

   Visit http://netgear.com/support , put in your (actual) model number,
and look for Documentation.  Get the User Manual.  Read.  Look for the
basic set-up instructions and "Troubleshooting".

> [...] have used the DNS servers recommended by Internode my ISP [...]

   I wouldn't worry about DNS until I got a basic DSL connection up (as
indicated by the DSL LED, among other things).