I have Roadrunner and a cable modem that has been hooked up to a computer for a couple months running fine. I set up a second computer, but when I hook it up to the modem I get bad service, ie it will work for a couple minutes then everything will time out, then it will start working again 30 min later etc. Everytime I switch computers I unplug the modem for about 30 seconds. When I switch back to the original computer it runs fine. Anyone have thoughts on what is wrong?