network not working right?

Well heres the story. I have 3 computers, desktop A, desktop B, and 1 laptop. both the laptop and desktop A can view desktop B's files. however desktop B cannot view the laptop's or desktop A's files. Also the laptop cannot view desktop A's files. I don't know why they can't plz help.
 
yes file and printer sharing is on. however i am the only computer running a firewall its windows firewall. The other 2 are not.
 
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