Connecting two monitors to a Laptop and two PC cases to a monitor are phenomena that face every office end user's daily working life. The configuration is simple enough that everyone having basic knowledge of hardware may connect them by himself. My aim is to achieve this without expensive hardware and with minimal cost. You may decide the appropriate alternative configuration that suits your hardware.
The first configuration -- how to connect extra monitor to a laptop -- will be explained. To connect these devices requires an LED flat monitor, a laptop and a monitor, and power and screen cables for monitor. Connect the external display to the laptop's external video connection on the back of the computer. An example of a VGA connector for a computer monitor and VGA port on a laptop is shown in the upper right.
Once connected, your laptop may automatically switch to the new external display, or you may be required to press one or more keys on the keyboard to switch to the external display. On Windows XX, navigate to Control Panel > View and Personalization. Select one of the devices as primary and the second laptop screen as secondary monitor or vice versa. You may operate both monitor as simultaneously.
At the second situation -- two PC cases to a single monitor -- we need an emulation type switch to connect and externally change cases. This switch has expansion slots such as main monitor, mouse, keyboard,case 1 and case 2 as USB or PS2. The switch is less than 30 USD available at computer hardware stores. The monitor VGA cables should connect to switch each of them. After completing the connections, the front side of the switch will have two buttons. You may use the cases by clicking the buttons.