1 computer's shared doc just dissapeared?

Hello,

I have 3 computers. One is hooked up to a modem and has a router which the
other 2 computers pick up on wirelessly. I ran the network wizards on each
computer months ago. They each have there own shared doc's in My Network
Places.

Then, on one of the wireless computers all of the sudden the main computer's
shared doc's folder dissapeared from the My Network Places. The wireless
computer that lost the shared doc can still print over the network and go on
the internet.

How can I get it to pick up the Main Computer (That's got the modem and
router) Shared doc in the Network Folder? Note: I've tried restarting each
computer all at once and seperatly! I just can't get it to pick up that
Shared Doc!

Please Help!