I have two computers connected through a Router on a LAN.
Suddenly, my 2 computers can no longer communicate !
When I go to >Start >My network places, I get a dialog box that only lists mailftp.mei.co.jp.
I cannot 'see' the other computer, disks etc.  Also, when I go to the other computer,  my computer has disappeared from My Network Places on that computer.
I can 'ping' both computers from my computer.
How can I reconnect the two computers?

   I have the same problem.  I have yet to find a solution.

This is a common problem - one computer decided it is the network server, usually the one with the internet installed. The other computer access the internet >through< the first computer? If this is the case ( and both are running XP) you can usually work around it by firibng up computer 1 first but without the internet and then fire up number 2 and ask for the internet from number 2. You should then have your network places.
If one computer is Vista - forget it.

   In my situation, I always can get the internet on both computers, I just cannot connect from one computer to the other.  In other words, I cannot move a file from one computer to the other or see what is on the other computer.  I have File Sharing on and I have tried using the Shared Documents folder but the Shared Documents folder from the other computer is either not there or not accessible.  The other computer is usually not shown on the network and if it is shown, it is not accessible.  Both computers are set up on the same network/group.