Have a small network I take care of with simple needs and they use Vista
machines (yuck). Anyway, one of the machines is a 'server' sharing one
folder. Every now and then this machine will stop sharing the folder for no
apparent reason. Can go back and share it again no problem, but in a few
months it will stop sharing it again as if it were never shared. It's
nothing the user of the machine is doing and no one else has access to it,
so the machine itself is doing it somehow.