What network are you referring to? Are you referring to the network connectivity that the machine can access the Internet, which the Internet is a giant network. Blocking those ports meant nothing, because once again, the router is setting there blocking those ports? Your machines are NOT in a networking situation on ports 137-139 UDP and 445 TCP from another machine over the Internet. That should never happen.
Yes, your machine is connected to the router and therefore it's connected to the Internet networking. Machines don't need to use 137-139 UDP or 445 TCP to network and communicate with each other there are
65,000 some other ports that machines can use to network on.However, for the MS O/S in order for the machines to network with each other to share files and the printer, the printer being on a host machine, then 137-139 UDP and 445 TCP are the *standard* ports that have been assigned to do that.
The fact is that you're not networking the machines in the first place on the LAN, even with the services for networking on the NIC(s).
If you actually were to try to access one machine from the other on your LAN, like logon to the remote machine and access its directories, etc, then you're going to have problems, because you have blocked the ports with the PFW.
The machines on the LAN are not networking, so it's a moot point that you have blocked those ports. And you're not going to see any problems with any networking because you blocked them, until you start trying to network the machines on your LAN.
It would be one thing if you passed that test with a computer that had a direct connection to the modem, which is a direct connection to the Internet, using a PFW.
That test really means nothing, because once again, the machine is setting behind a router. The router has all ports closed by default. It's a bogus test that you're doing.