LOOKHere
That software is pretty cool.
This may seem like a stupid question, but Computer A (the computer with internet) has a cable/DSL modem with lights labeled "PC", "Cable", "Data<Send, Receive", and "Power". There is no router with computer A.
Computer B (the other computer in the house with no internet) has a Linksys wireless card with an antenna installed.
So is the problem that Computer A does not have a router? If so, should we have been provided with one when buying the internet service in the first place? It seems that my previous roommate was provided with a router upon receiving the service.