Lost My Network Places across the intranet

I have a 5+ computer network at my church.
4 wired LANs and 1 (or more, depending on who has their laptop that day) wireless connections.
This system has worked flawlessly for the past 2 years.
Starting a couple of days ago, I have been experiencing a problem.
When you open up "My Network Places" on any of the computers it doesn't show any links to the other computers.
Placing a direct connection shortcut on the desktop of any of the machines (target = \\computer name\folder name) allows access as normal.
When using Windows Explorer, a pop up tells me that the network is: "not accessable".
The router is a Netgear WPN824V2

Anyone have any ideas?
This is annoying because I'm the only one here who has any knowledge of networking, so it is up to me to refit each computer with the appropriate shortcuts.