please advise on IP conflicts/smart home

[turbo24]

Heres my 411:

My co worker is setting up a wired network in his home (doesn't want to go wireless at all) and he is also incorporating the network into his soon-to-be smart home system. (all pcs run windows xp) So he has this whole panel set up, with a Leviton switch and a Leviton gateway. He has DSL service.
If the modem is connected to/thru the gateway, he cannot get online at all. (It will say media disconnected if ipconfig is performed) If the modem is connected to the switch only, and the gateway is removed altogether, then he can get online. However if another PC tried to get onto network, it will be assigned the same IP address as the first pc, thus creating a conflict and kicking one or the other off.
The gateway is default 192.168.0.1 and so is the modem. The Leviton people told him that the two units (modem and gateway) having same config IP is the problem, but he cannot configure the gateway to be any different - he cannot acess it at all.
I tried to overcome the conflicting Ip addresses by assigning one of the secondary computers to a specific address, using same default gateway and dns etc, and that worked - but only to get him connected to the network (and the lights on switch were showing activity and such) but he was not on the internet still. Network connection there, not internet.
Now I am pretty much clueless when it comes to smart home panels and so I guess his problem is beyond me. (Not that networks in general are really my forte anyways)
I can offer up more info probably if you need it, but does anyone have any ideas ot thoughts on this one?

[leroys1000]

You may have a problem with the switch having the same IP also,or not.
Connect the computer with the static IP and connect the
gateway to the switch.
Open your web browser and enter http://192.168.0.1 and click go
or hit enter.
You should land on a login prompt.
Login is usually something like admin with the password blank.
You will need to check the manual for your hardware.
If you get logged in,you can change the IP in the setup dialog.
Once that IP is change,repeat the steps with the same address above.
If you land on another setup page,change the IP again.
Once that is done,you should be able to connect the modem and it
will assign IP's for the entire network.
You will then need to run the network setup wizard for each newly
connected computer and select it is connected through a LAN.
Remember to write down the new IP's as you change them,as you will
need them if you need to get to the setup again.

[z1p]

What is the make and model of the gateway and the modem?

[turbo24]

leroy - if the gateway is connected at all, the computer is unable to get to the config page. If the computer connects to the switch and the switch to the modem, it can get online but going to the config page is going to just be a config for the modem itself (obviously)
I think you are correct about the conflict but how do i resolve if i cannot get to the config page??

z1p - the modem is a basic att provided speedstreem / siemens one, sorry i don't know model! But gateway and switch are Leviton
the gateway is here:

http://www.levitonhelpdesk.com/catal...bilityConnect=

the switch is here:
http://www.leviton.com/OA_HTML/ibeCC...3&beginIndex=0

[leroys1000]

Try it without the gateway first and see if you can get a setup page for the switch.
Don't connect the modem.
Reading the basic instructions they give for the switch indicates both
devices may nedd to be power off when connecting.
Some type of auto detection at power on?

[turbo24]

yes, i did try that actually. If i disconnect modem out of the loop and connect computer directly into the gateway, I get ZIP. i mean - the activity lights on gateway go blank, like its not even connected!

[turbo24]

sorry i should have read your reply better, i aslo did same with switch, i do get lights but cannot connect

[turbo24]

okay - you knwo i did initailly have eveything off when making connections but after a while i did not take that step. i just tried connecting/disconnecting with it on...i did not even realize...hopefully that was the problem!