Network problem

I have the simple p2p network setup via a router...wired for now. One
computer sees the other, but the other says its after logging off (
which I never had to do previously ) that it cannot reconnect network
to other drives. Click My computer to see the status. What status? It
just shows itself. I had this working just fine before I had to
reinstall XP and there use to be a icon shown on the system tray
informing me of its connection..now I do not see that anymore, also,
when it was working fine, I never had to Log off, in order to see each
computer.