I had a similar thing happen to me though I don't remember anything
freezing. And it happened on every computer in my network, not just the one
I might have been using at the time.
Have you tried to create a new workgroup and see if it works?
I did that and now see 2 workgroups listed in "/my network places/entire
network/microsoft windows network/." When I try to view or use the old group
in network places I get an error about it not being accessible and no
permission, etc. I can still use shortcuts like "\\(computer
name)\foldername" to access the other computers but can't use my network
places. It is annoying to see the extra group listed in Explorer but I'll
live with it.
So it seems to me, as inexperienced as I am, that something has locked or
corrupted the old workgroup in some way but the new one is fine and the
links to shared folders, new or old, are fine too. Creating the 2nd group
solved my problem though I had to do it on every computer in the network if
I want to use my network places to access them. Saving shortcuts like
"\\(computer name)\foldername" would save you the trouble of changing every
computer.