OSX 10.3.9 networking help please

[Voryn]

I have a mac (no i dn't know what model) but its a g4. Its on a LAN and it can access the internet BUT now it will not connect to any other mac on the network. I could use a few suggestions. Restarted router, i have double checked all the configurations on the mac to make sure its the same as before (as well as another mac) . The only thing to change in the last 24 hrs is a power lose to a server, a copier and a router in that area.