|DO NOT plug in or unplug a monitor's video cable into / from a video port while the computer is running. Doing so can damage the monitor's circuits and/or the video adapter's circuits. |
Some laptops will display on an external monitor without you having to do anything.
If you get no video on an external monitor, some laptops have a key combo that you must press to toggle the display to external video only / sometimes both / built in display video only - see the Owner's or User's manual for the model.
If you get no video on the external monitor even so before Windows starts to load, you have the very rare case that the circuits for the default VGA support of the video adapter, which needs no drivers, are damaged - since most laptops DO NOT have a video CARD (a CARD is removable) and instead have a video adapter built into the mboard, usually the only cure for that is to replace the mboard.