If the firewall is off then ports 137 and 138 aren't being blocked. There's no "enabling" of the ports. They're either blocked by the firewall or they're not. The only thing other than that is the application has to be listening on those ports. That's it.
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CompTIA A+, Network+, Server+, Security+
MCTS:Windows 7
MCSE:Security 2003
MCITP:Server Administrator
MCITP:Enterprise Administrator
MCITP:Virtualization Administrator 2008 R2
Certified Quest vWorkspace Administrator