I have a CPU and I'm hooked up to High speed cable. My girlfriend moved in and wants to use her Laptop. The cable people told me to hook up her router to my modem. But my CPU ethernet port does not work. I run from the modem to a USB port on my computer. All the routers use an ethernet port. How do I get her laptop working?

I'm not certain that's it. There is some amount of configuring to get a modem to work with Ethernet and/or USB. For one, you can't generally connect the modem to the PC without a cross over cable or a hub/switch. You can if one has an Auto MDIX (?) port.

Then there is NAT and DHCP that needs to be configured on both ends to get one computer to work.

Then to add the other router, you have to place the modem in BRIDGE mode and make the new router do DHCP and NAT.

Then who knows if this router is a wireless router, so you have more configuring to do.

The steps are messy, but having the model of the modem or a link to the manual would help bunches.

Knowing if the Ethernet card or modem supported Auto MIDX (?) would help too.

And so would knowing whether you get a response from a "ping 127.0.0.1" from the command prompt.

Getting a link light on the PC and modem is one of the first steps.