UltraVNC

UltraVNC is a powerful, easy-to-use and free software that can display the screen of another computer (over the Internet or network) on your screen. The program allows you to use your keyboard and mouse to remotely control other computers. That is, you can directly work on the remote computer as if you were sitting in front of it. With the SingleClick add-on, you can also provide remote helpdesk support to your customers, for example.