My friend and I used his crossover cable to network our computers and it worked fine. He let me borrow it so I could attempt to do the same thing with my and my brothers computer, but it isn't working. It keeps telling me that the network cable is unplugged, but this isn't true. I have the proper network protocals installed, and my brothers computer does not tell him the cable is unplugged. Any ideas on what I may be doing wrong?