Networking 2 computers

I have a HP Pavilion desktop 6260a and a HP laptop dv6000 both operating
Vista Ultimate. I have managed to get the two computers to see each other
and to allow file sharing through a public folder (disabling the Norton
firewall to allow me to do this). The trouble is that whenever I enable the
firewall, I lose connection to the networked computers. Can you please
advise how I might get around this.

Also...is there any way that I can have windows mail and windows calendar
synced so that I can see the same email and the same calendar (for
appointments) using either computer.

thanks