Dlink DI-624

I'm not sure that we can offer any real advice as there are numerous possibilities here. You'll need to give us an overview of the Network and exactly what is no longer working.

For instance does the Internal LAN work and you can transfer files between the different computers but not get a Internet connection on any?

Does anything at all work here?

If you unplug the D Link device does the internal LAN Start to function again?

But regardless you need to look at the actual Settings of the D Link Device and compare it to the settings of the older device things like DNS Issuing the actual ISP Settings and so on are the important things here. If the Old Device was issuing the DNS and this one isn't that could be your problem to begin with or similarly if the old one was not issuing DNS and a Internal Device like a Server is and the new D Link is set to issue DNS Addresses that could be your problem as the 2 devices issuing the DNS Addresses are conflicting and preventing he Internal LAN for working correctly.

Col