Just deleting the dhcp.leases file did not work. I think when I shutdown the system a script wrote out the current information again which had Knoppix as the host name.
I ran "dhclient -r eth0" and then emptied the dhcp.leases file. I opened up a text login window and could see that the Knoppix hostname was gone.

You are saying that the comcast dhcp server stored my "Knoppix" hostname and returned it to me in a dhcp request after I rebooted and requested a new lease.