network connection problem

Hi there. I just went to comcast and asked to upgrade moderm. I came home and switch moderms. Now my internet is not working. (I'm typing this thread from my blackberry) I search some threads that simple common as problem I am having. I used window key with R and typed COMMAND. I typed ping with numbers. It said pinging 216.109.112.135 with 32 bytes of data: request timed out, request timed out, request time out, request timed out. Ping statistics for 216.109.112.135: packets: sent =4, received = 0, lost = 4, (100% loss).

The old moderm was Terayon and I switch to new moderm is motorola sb5101

My dell is 2400 with XP. Any idea how to solve it? Thanks.