I have a shared file set up on 4 computers. The main computer rebooted and now when the other computers try to connect to the network files we get the error the network path was not found. This connection has not been restored. Can someone tell me what to do

When you set up the file share on the other computers, did you use IP addresses or the computer name?

If you set it up with IP addressing, more than likely your server was issued a new IP address at that time.