I had three computers networked. All had internet access and could access anothers files and share. I recently had to replace computer #2. Now, still, all three have internet access but #2 can not share files with #1 or #3. I have sharing allowed on all, as before, but #2 is not accessable. Have I missed something? My network is wired and connects thru a router. Nothing has changed on #1 or #3. I'm about to give up. Any ideas will be greatly appreciated.

Problem solved!!!!!!!!!!!!!!!! It was a firewall problem. Thanks anyway.