Comcast Internet help

[pck3]

I am new to an apartment with comcast internet. It works when hooked up to xbox for xbox live, but when hooked up to the computer it doesn't work. Any ideas. I tried renewing IP and it says cannot reach dhcp server.

[RandomGuy]

i haven't had comcast for a long time but back in the day you had to call in each MAC address connected

[x Resilience]

You have to restart the modem every time you plug it back into the computer, thats how I had to do it until I got a router.