Can't find the solution in other posts so far.  A curious problem.
Couldn't ping either way in a 2-computer network. Disabled the
firewall and turned the router firewall on and now can ping both ways.
On computer #1, I can see the shared folders and files on computer #2
and  print to its shared printer.
On computer #2, I can see the shared folders on computer #1, but
cannot access the files, but can print to its shared printer.  Also
have a shared USB drive that is visible, but not accessible.
I've tried unsharing and resharing the folders to no avail.
What am I missing?  This was working several weeks ago but has all of
a sudden stopped.

- Well you have not mentioned the OS on the both machine
I consider it be XP 32 Bit, bcz if one is 64 bit FS will not work.

- Make sure you check the Simple file sharing on both machine
- Booot both the machine in Safe mode with networking & then check
- If the machines are under the AD enviorement make sure you disable the
default domain policy.
- Make sure both the machines are in the same work group
- enable the guest account on both machine

Still have problems feel free to revert.

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