"going from DSL to cable with 3 computers*"

* Otherwise known as snatching yourself bald-headed in frustration

I have one computer hooked to cable with no problems. But when I try to network two computers together neither one will connect; each one will connect when by itself - one to cable, one to DSL.

All the hardware is reported to be working properly, and I have tried setting up a network, using Windows XP on these first 2 computers (the third one uses Windows 98).

I have an installation cd that the cable guy left but the menu on it says nothing about linking computers, just installing drivers and stuff like that. I also have a usb cable that came with the cd. And I have a Linksys router.

So my question is this: how the heck do I get three computers networked and if I need to use the usb cable how do I hook up the third computer when the router has no usb port?

Please speak in very small English words when replying; I'm just a sweet old lady that is quickly losing it.

Thanks! Ü