i have lost one wire of the eight in my network do i have to re-run wire or can i switch some around ????

What do you mean, "i have lost one wire"? Do you mean that connection no longer works, or did someone remove the cable? (I'm assuming the former.) If that network port on the switch or router has gone bad, then you can unplug the cable from that port and use a different port. If the cable itself is bad (e.g., a rodent has chewed thru it), then you would have to replace the cable.

this depends on your setup. if you are using straight through cables, then only 4 are used/needed, if you are using cross-over cables, then all 8 are needed. (google to see what ones are used.) if you know the none working cable, just switch it with one that is not used and is working. Basically as I see it, if switching ports on your hub doesn't work, and you know that only one wire in the cat5 cable is bad, (i don't know how you would know), then try switching, if nothing else, it just wastes two cat 5 ends and a few inches of cable, and i'd rather do that then reroute cable, (especially if it is running through the walls/roof) Hope that helps! George Please respond after you have solved your problem to notify who helped you and what solved the problem. Both sides benefit when you do.

Are you sure you weren't reading an article on 1000 Mbps crossover cables? I've been working with computers and networking for many years and I've never heard of a Cat5 - 100 Mbps crossover cable using any more than the same 4 wires used in a straight through cable. A 1000 Mbps cable (crossover or straight through) does use all 8 wires. Depending on which wire is "lost", and where the break in the wire is, you have options. You could put a new RJ-45 end on the cable if the wire is broken right near, or inside, the RJ-45. If it's in the middle, you could solder the wires back together. If it's a wire that's not in use you won't have to do anything.

sorry about (need more info). but you have answered my question . FYI - 4 computer home network , wires in walls , roof , and crawl space . i had added more insulaton to the attic and lost one line. yes it was the lostest- how i know orange/white wire broke ? remove cat5 outlet for wall , remove female jack/plug in , twist wires together in groups of two, goto other end remove jack/plug in , check each group for continity with meter, one group dead , retwist that group with other , meter again .orange/white wire broke.. THANKS- again for the help herkamer

Curt R: I believe that you are correct. I was kinda refering to that with a cross over cable the wires have to be setup in a specific order, and if one of them is off or not connected, then the whole cable doesn't work (for cross-over purposes). I am sorry for the confusion if i caused some. George Please respond after you have solved your problem to notify who helped you and what solved the problem. Both sides benefit when you do.