Hooking up 2 PC's to 1 internet

Simple I know, but aparently not always.

Ok, Networking is far from my strong point although I have hooked many up in the past.
So a few days ago a friend asked me how to hook up his girlfriends PC onto his internet, "Simple" I said, famous last words.

As far as I'm aware and the way I've performed this task god knows how many times you go...

Connection (in this case being cable) - Modem (in this case a motorola) - Router (in this case a Belkin 4port + wireless) - PC(s)

Didn't work, as soon as I plugged the router in even though it showed a connection on the lights, niether PC was able to connect.
Remove the router from the equasion and both will connect (1 at a time)

Cables are fine, tested and working.
PC's both connect fine in tests.
Modem produces connection fine in tests.
Router hooked up to different hardware worked fine both wired and wirelessly.

I didn't fight with it too long because I'm thinking there's a problem between the modem and router.

I've never come across it but how often do you find a modem not compatable with a router?

Or any other suggestions?

Modem = Motorolla (not sure on model)
Router = Belkin Wireless G (F5D7230-4)
Both Pc's running Win 7
Cable connection of 2meg

 

before you stick any cables in to network your systems, you have to configure your router to talk to modem. it varies by make and model, so see if you can find any documentation for the router

 

I just plug mine all together, then power up the modem and router. PCs already in line.

 

To Geminiione's point depending on your ISP service there may be some other things to do. Sometimes the modem will not talk to another MAC address unless reset. Example...the modem was talking to the PC with the PC's MAC address. You now connected another device with another MAC address to the modem.

Lets try this. Turn off the modem, router and PC. Power up the modem and wait 30 seconds. Then connect and power up the router and wait another 30 seconds. Then connect and power up the PC and see if you can get on the Internet.

 

Maybe this can Help.

How to Fix Cable/DSL Internet authentication (password) - http://www.ezlan.net/broadband.html

 

Thanks for the explination although I have done that, about 12 times lol, I always restart everything when anything to do with internet goes pear shaped.

@hrlow2... lol Thanks dude , actually this is whats getting me, I've always just hooked it all up and away it went.

@Geminiione... I did think of that and tried the IP's I know but couldn't gain access to the router, having said that I did get called away from the problem before I could really explore that option. Had forgotten about it until you now mentioned it, will try it and see how it goes.
I've also brought the router home with me so I can just test it here and see if it works or not. He told me he had the router working but I've never actually seen it working so I'm not ruling that out just yet.

Will report back when I've tried some stuff, thanks guys

 

the quick way to find the ip address of the router is type at the command prompt "ipconfig" the gateway will be the address of the router.

 

OMG you're right, I must have been have asleep when I was doing this lol, thanks.

 

Hopefully you have fixed it, if not try pinging the router and the other PC.
If that works at least you are wired, try ping google.com from command prompt.
I assume you made each PC work through the cable modem.
My modem has a four port router built in and DHCP. I need more connections so I added a switch. If you added a router to a modem that has one built in it causes problems.