Viewing network computers

I have a network at the office that has 15 computers on it all running Windows 7. Everything has been working fine but I have something very strange happening right now.

I am putting a new computer online and when I go to the network window only 7 of the computers show up and unfortunately the file server isn't one of them so I can't establish a connection to the shared files. All the othe computers in the network are showing the same thing in the network window. Since they already had maps to the shared folder they are still able to access files through that mapping.

You can still try to access the server with its IP address. In Explorer address bar, write \\Server_IP_Address (something like \\192.168.0.10)

Also try:
- Restarting your router
- Check the services mentioned here (other than HomeGroup ones) - Homegroup - Create
- CHeck your firewall settings on the PCs not showing