What setup did you have before?
Do you mean the machines can't see each other?
Make sure they're both set to 'Home' network type, and not 'Public'
If it was just two PCs hooked together you probably had to set IP addresses manually as there was no DHCP server in the network to do it automatically.
If you did this, you need to set IP config back to Automatic because there is now a DHCP server in your network (the superhub).