If I hook another computer up in my house, on a separate cable (cable net) will it slow my original computer down when both computers are accessing the web? I have a cable in my basement that was only used for cable until my brother in law moved in. He found out that the cable will work for his Xbox and has been using it for xbox online, and now he wants to hook a computer up down there and use my internet. It is not a roadrunner only line, it comes off a splitter. It works fine for his xbox, and I have not seen any slow down upstairs, but I want to be sure that it won't interfere if he runs a computer down there off that line. I need to know if this will cause me any problems with my net upstairs. Thanks for any help guys.