VBE 2008 How to handle disconnect

Hello all. I am building a chat client/server.

And I can connect and chat just fine, but when a user disconnects, the server does not recognize this and acts weird, often spamming the last message that was sent by the user..

Also, it's like the client does not disconnect from the server even when I close the client app. Once I exit the program, VB acts like it is still debugging. Once the server is shut down however, I get this error:

IOException was unhandled
Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.

serverStream.Read(inStream, 0, buffSize)

I don't know how to make my client and server accept the fact that a client has disconnected... Any help?? Thanks.

P.S. I attach images of the error I get from the server, the bigger one comes first followed by the smaller image.