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I have had working file sharing with that firewall up until this happened
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Did it suddenly stop working or did you change something on your network?
Here are a couple steps for you to try:
1) Try changing the Node Type to hybrid on all the machines.
2) Go to your Administrative Tools menu in Control Panel. Go to "Local Security Policy". Under "Local Policies" (2nd folder on my machine) click on "User Rights Assignment". Make sure that the user "Everyone" is included in the policy "Access this computer from the network".
We'll see what these do and go from there.
I also found this interesting networking
diagnostic page . It might be worthwhile taking a look at, but I have a feeling that everything is ok.