When setting up you network did you change the name of the network? On XP computers it's called MSN, workgroup and needs to be changed to homegroup. On 7 it's homegroup.
I see your running both McAfee and Norton, are they both Anti-Virus software? If they are you going to run into a lot of problems. You can only have one Anti-Virus app running at a time. Also those two are resourse hogs, I would recommend getting rid of both of them and using MSE (Microsoft Security Essintals) or Avast, both are lite and free.