home network cabling

I've been trying for a week to get a second computer online with my cable modem connection. When I run a Cat 5 from my Linksys switch up the stairwell in the house to the second computer, I'm fine, but when I attempt to connect via a line run through the walls (worked fine as a DSL line previously) I get nothing - no solid lights on the switch, no connection. I have purchased two new cables now and tried to solve the problem, but no luck. Is there a limit to how far that signal can run to the second machine (the working line running up my stairway is approx. 50' whereas the line I want to hide would be 100+)? How can I test the integrity of the lines I'm attempting to construct to know I'm RJ 45-ing them correctly? Any help, please - I'm going nuts on this.

5. RE: home network cabling
lbyard Sep-20-01 10:59 PM
In response to message 0

>Is there a limit to how far that signal can run to the second machine..?
The limit, the total distance from one computer through the switch to another computer, is 100 meters (384 feet) for a 100BASE-TX network, about the length of a football field.
>How can I test the integrity of the lines...?
I test them on my existing network by copying 100 MBytes from one computer to another and measuring the time that it takes (http://duxcw.com/digest/Reviews/Network/dlink/dhn910/dhn910-4.htm).
>How can I ... know I'm RJ 45-ing them correctly?
By reading and carefully following http://duxcw.com/digest/Howto/network/cable/cable1.htm, and then testing them. Larry