Make sure you don't have Windows Firewall enabled except on the PC directly
connected to the internet. That can affect network access in weird ways.
Also, make sure you have the same workgroup names for all of the PCs. I'm a
little confused because it seems like it was working for a whle since you
were able to map the drives in the first place (I assume you checked them
once they were mapped) - and you wouldn't have been able to do that if you
had no network access whatsoever. Try making a new network connection to
one of the network resources to see if it comes up in the network places.
Also, even though you can't see them on the list, can you connect to them
from the command prompt using net use?
