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Is it possible to make my laptop's screen act as a second monitor for my desktop computer?

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this video seems to indicate that no additional software is necessary: cnettv.cnet.com/use-your-laptop-second-monitor/… –  RamyenHead Feb 17 '11 at 7:14
@RamyenHead: Even though the link you posted suggests that it enables you to use an old laptop as second monitor, when watching the video you will realize that they just use a second monitor with a laptop -- no desktop PC involved ... –  f3lix Sep 13 '11 at 8:10
See newer answers for newer OSs, like this answer. –  Ƭᴇcʜιᴇ007 May 23 '14 at 17:06

7 Answers 7

up vote 37 down vote accepted

Here's an interesting freeware solution:


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1. Windows Server 2008, Windows Vista and Windows 7 support is limited. (Aero must be disabled manually), and some BSOD reported under Windows 7. 2. It might be good to note that it is using Network connection between these computers –  itsho Jul 22 '13 at 13:41
Synergy has no such requirements or BSODs. –  Collin Grady Dec 28 '13 at 7:42
Doesn't work with Windows 8. No longer being developed. :( –  Ƭᴇcʜιᴇ007 Apr 9 '14 at 15:13

Maxivista is a commercial software that lets you do this.

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It's worth noting that there are some limitations when using it with Windows Vista. See here: maxivista.com/docs3/09/sysreq.htm –  Joe Schmoe Jul 29 '09 at 20:50
@JoeSchmoe The irony: You can't get the Maxi out of this software on Vista! –  Annonomus Penguin Dec 15 '13 at 20:45
Doesn't work with Windows 8. No longer being developed. :( –  Ƭᴇcʜιᴇ007 Apr 9 '14 at 15:11

The following product is advertised as compatible with Windows 8 :

Air Display

Air Display is an app that lets you connect an iPad, Android tablet, or Mac or Windows computer as a secondary display to a primary Mac or PC desktop using your wireless network. By default Air Display is set to function in Extended Desktop mode.

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ShareMouse is more like a software KVM; it doesn't allow you to use your laptop's screen as an additional monitor. Rather, it allows you to control your laptop (or other computer) with your primary computer's keyboard and mouse. –  Josh Apr 7 '14 at 19:41
Similarly, Multiplicity describes itself as a "Virtual KVM switch" that allows you to "Control up to 9 PCs and displays with one keyboard and mouse." It does not appear to allow you to use the laptop monitor to extend your desktop. –  Josh Apr 7 '14 at 19:42
Yes, that's exactly what MaxiVista and ZoneScreen do--but they don't support Windows 8, which is what I need. –  Josh Apr 8 '14 at 0:27
It says "If you wish to use the remote control feature on Windows 8 computers, please check out our new software "ShareMouse"". It is very clear. I am not interested in the remote control feature, nor is this question about remote control. Maxivista does offer BOTH remote control and extending your desktop, which is why, the developers suggested ShareMouse for users interested in remote controlling another machine. –  Josh Apr 8 '14 at 9:09
Air Display technically works! However, I am extremely disappointed in the performance. I've got my two PCs connected via gigabit ethernet with nothing but a gigabit switch separating them, and the screen refresh is still slow as a dog. You're constantly overshooting things with the mouse because of the latency--the mouse pointer keeps moving for a second or two after you've stopped physically moving the mouse. At any rate, it does technically work and answer the question, so if you'll remove the ShareMouse and Multiplicity links from your answer I'll upvote it. Thanks! –  Josh Apr 8 '14 at 19:45

Though perhaps not exactly what you want, you could use synergy between computers (OS independent too!). As well, you can copy both text and files across the computers, so for all intents and purposes they act as one computer (though still use their own hardware).

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That's not what's we seek. :) The goal is to use a laptop (or another PC) as a secondary monitor for the main OS. Making it equivalent to a second monitor, where as this is more like a KVM without the "V". :) –  Ƭᴇcʜιᴇ007 Apr 11 '14 at 19:09
You can't drag an application between screens, so it's hardly the same "for all intents and purposes" –  Ben Voigt Apr 13 '14 at 19:52
Exactly what I was looking for when googling and coming to this topic, so thanks! –  Koren Feb 26 at 15:41

You can also do it via remote assistance, if you have a second output on your display adapter. I mean that you have to be able to hook another display to your desktop PC via cable. The remote assistant is able to show the secondary desktop (as well as the primary) even if the monitor is not physically hooked.

No third party programs required for this solution.

Edit: In details, if you have a multiple outputs in your display driver but no monitors (not hooked), you can do the following (works for nvidea quadro 2000 and win 7):

  1. go to: nvidea control panel -> workstation -> view system topology
  2. from there: (main display port) manage EDID... -> export EDID...
  3. same place: (secondary display port) manage EDID... -> load EDID... (choose the file that you saved in the previous bullet)
  4. Now you have a 'virtual' secondary screen and you can use remote assistant to zoom to it

This trick does not require admin rights nor extra software.

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On current version of NVIDIA Control Panel (7.2.710.0) [NVCPL.dll is], I couldn't find "workstation" option. here's a screenshot –  itsho Jul 22 '13 at 13:35
My version for NVCPL.dll is (previous one) and I have this workstation. The system information (button in your screen shot lower left corner) shows workstation as a server in components tab. The corresponding dll:s are nvWSS.dll and nvWSSR.dll. You could check if you find these dlls in your computer (the workstation mode might require some additional enabling/installing/etc). –  Juha Jul 29 '13 at 10:02
I do have those files. I've searched a bit and it seems that Workstation mode is available only with NVIDIA Quadro cards - which I don't have. Please correct me if that's incorrect. –  itsho Jul 29 '13 at 10:20
You might be correct. I tested this on home and office and both seem to have quadro. Anyway, the secondary display should not be dependent on the control panel. The logic goes (1 to 3 should work independently of the graphics card, bullet 4 I am not so sure): 1. You have two output display ports. 2. You attach two monitors. 3. You can connect to your secondary monitor via remote assistant. 4. It is possible to skip step 2. –  Juha Jul 30 '13 at 4:30

You can use your laptop as second monitor using " Real VNC " Software. I have done many times you can operate by laptop or desktop anyone and you can see in other.

Update :

I misunderstood the Question. to use your laptop screen as the extended screen use Zone Screen for Windows 7 or lower versions.It is no longer developed. See the first answer.

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By using RealVNC you get a mirror image of your primary display. I think the asker wants a way to get more usable desktop space. –  mtak Apr 11 '14 at 12:43
+1 again, as it is very well possible to tell your 'main' computer to 'pretend' there is a second monitor on your gfx-card and then tell VNC to connect to that one. FYI: I'm actually looking at it right now and although it lags badly, it works just fine to show debugging and error information on my other laptop. –  deroby Dec 16 '14 at 11:09

dmx.sourceforge.net - have to fool around before you can get it to work. But you can create video-walls with it. (or just two screens)
Example : buy a raspberry pi for 30$ and a hdmi screen for 140 $ ... no : buy 15. Put a HQ switch between all. install dmx (Distributed Multihead X Project) and you have a nice 7920x4320 desktop.

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protected by Ƭᴇcʜιᴇ007 May 23 '14 at 17:07

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