Sup yo....I am trying to help my friend out with this problem

He has 3 computers on his network all in the same workgroup.

Computers A, B, and C.

Computer A can see B, and C. It also has access to all the shares.
Computer B can see C and access all of its shares.
Computer C can see B and access all of its shares

B and C can see A, but can't access the shares.

I even went to the point of sharing the entire drive on A and still nothing.

No firewall programs.....File Sharing is enabled on all 3 computers....

What am I missing. I feel so stupid. I have the same setup at home and it works just fine for me.