Keep loosing Network Connection

I have two PC on my network. I have static IP's in them.
My cable internet works fine. But, I have a program that
is networked between the two pc's. I have one set up as
the server, and the other is the workstation that gets its
information form the server. When i shut the workstation
down and reboot it back up it will usually once come up
and reconnect to the network drive. Then after that I
shut it down and reboot and it comes up and will not
reconnect to the network drive that I have mapped. Then I
go in to My Network Place to try to reconnect, but it will
not let me view my workgroup. When i hit Ctrl+Alt+Del it
says My Network Places in not responding. If I wait a
little while it will finaly let me in to reconnect my
network drive. Does anybody know why this is? My XP
firewall in not enabled.