Initially I was using a switch to connect all my 5 desktop systems using one of them as my internet server/gateway. On that particular internet server-desktop pc, I use the Sierra wireless Aircard 580 modem which I adapted with a pcmcia-pci card. I used the ICS to share out internet to the other systems using dhcp configuration. Each desktop carries the (192.168.0.last dhcp assigned digit) while the internet server desktop carries 192.168.0.1 as the gateway. Everything was working perfectly until I introduced the D-link router into the LAN.
Initially I connected the Ethernet cable of the internet server desktop to the INTERNET port of the router but the indicator remained a solid red color. Also, I couldn’t get the 192.168.0.1 on my browser. So I connected the internet server desktop directly to one of the LAN ports of the router (using one of the 4 LAN ports) and then connected my switch to another LAN port of the same router. Then I was able to get the http://192.168.0.1 ip to enable me configure the router through the browser.
At this stage, the router still could not get internet connection from the desktop internet server. (Please note that all this while, I was reading up everything the manual says as well as visited many forums for a way out).
I finally thought the router’s internet connection port was faulty so I returned it in exchange for another one. Alas! The issue remains the same.
I decided to try out another method which I picked up from one of the forums I visited, by changing the ip of the router to 192.168.0.2 while my internet server desktop retails the 192.168.0.1 for sharing internet. I then reconfigured the router accordingly to use the 192.168.0.2 ip address.
The situation now is that all the other 4 desktops upon reconfiguring them for dhcp internet access keep using the router’s ip (192.168.0.2) as gateway instead of 192.168.0.1 but without internet connection while all the systems can ‘see’ one another and share resources (including the internet server desktop) without problem.
Kindly inform me what I have done wrong or yet to do right.
Thank you.

Why not use the router as the gateway instead of the pc unplug the modem from the pc and plug it into the wan or internet port of the router power cycle the modem and router and all machines should be on the internet.