Introduction
X-Windows or X is the UNIX graphical user interface. While it is not as "pretty" looking as Mac, and Windows it does have features that are powerful one of which is the separation between where an application is running, and where it is displaying. The server that is running the application is known as the X-windows client, and the location where the windows of the application are being display is known as the X-server. There is nothing that says that the server, and client have to be the same piece of hardware which gives you the ability to access remote applications from your desktop.
There are two approaches to running an X application. First, you can run X-server software on your computer. In fact, if you are logged into a desktop or laptop running Linux, you will already be using X and running an X-server. PC and Mac users can download X-server's though. With an X-server, you can use ssh to connect to the remote system, and then run X capable applications which will display their windows on your computer. The problem will be that if you disconnect from the remote system, then the X application will also be terminated. The second approach is to use Virtual Network Computing or VNC. With a VNC connection you get the full Linux desktop environment, and you can also disconnect from a session and reconnect later.
Please follow all instructions for doing setting these