Can I use my laptop display for my desktop?

Cause:

Users may wish to use their laptop display for their desktop for any of the below reasons.

1. Their display for their desktop is bad or has failed.
2. They feel the laptop display is better than the display on their desktop.
3. They cannot afford a monitor for their desktop computer.

Answer:

Note: This document is pertaining to users who wish to user only their laptop display as a primary or secondary display and not the computer.

Unfortunately, it is not possible to directly connect your desktop computer to your laptop and use it as the display. A laptop communicates to its display much more different than a desktop.

However, if you have a good understanding of electronics, a lot of time on your hands, and no longer need the LCD on the laptop it is possible to remove the LCD from the laptop and manually solder a connection from the desktop to the laptop. However, because of the complexity involved and all the possibilities there could be Computer Hope cannot post information about how to do this.

How can I connect an external monitor to my laptop?

Almost all laptops, especially those made within the last few years, have the ability to connect an external display, such as a CRT monitor, flat panel display, or Projector, and have the display sent to that device instead of to the laptop display.
Connect the monitor, flat panel, or projector to the laptop's 15-pin video connection on the back of the computer as shown to the right. Once connected, your laptop may automatically switch to the new external display or you may be required to press a sequence of keys in order to switch from the laptop to the external display.
The key sequence can vary depending on laptop, however is often either: Fn + F3, F4, F5, F8, or F9. This means if you were fore example to press and hold Fn + F3 at the same time it'd switch between your laptop display to your external display. The function key will often be labeled as CRT/LCD and/or have a picture of a monitor on the key or close to the key. Unfortunately, the keys pressed to switch displays is dependent on the model and manufacturer of the laptop. If none of the above key sequences work, consult your laptop documentation or consult your laptop manufacturer.
Some laptops also have the ability to have the display on both the laptop and external display and/or one or the other at a single time. Laptops with this ability can switch between these modes by continuing to press the same function keys until in the mode the user wants.

How do I disable the auto-switch feature?
How can I specify the default display as the external display?

Although not available with all computers, some computers will allow you to enable and disable the external display auto-switch feature and/or specify which display you want as the default, through the CMOS setup. 

How do I change the resolution on a monitor connected to a laptop?

Unless the monitor is detected or setup in the operating system, it may not work properly or will only display at the default resolution. If you wish to change the external display's resolution, make sure the monitor is detected by the operating system.

Microsoft Windows users can verify the monitor is detected by looking in the Windows Device Manager and making sure a monitor is listed.

Linux users running X Windows or a variant may need to modify their XF86Config file and add the display settings for the external monitor or projector.