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Can I use my laptop as a second monitor for my desk computer?

I would like to set up a dual screen display on my pc. Before buying another monitor, I'd like to try doing so with my laptop's screen.

I've got a Lenovo IdeaPad S205, and was hoping to hook my PC to this monitor so as to use the laptop as a monitor. After reading numerous guides on the internet, I learned that a VGA cable is not the way to go since that will not accept input on the laptop.

Are there other alternatives? I have read that it is not possible unless special networking software is used (i've tried it myself but my connection is not fast enough to work in this manner). However, I went to an office a few days ago and saw that most staff were using laptops as secondary monitors to the PCs. And they were all connected by a cable.

Could anyone explain what is needed?


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marked as duplicate by ChrisF, bwDraco, Indrek, Nifle, soandos Sep 23 '12 at 1:39

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

If you went to an office a few days ago, and saw that most of the staff were using laptops as secondary monitors and they were all connected by "a cable".... and you want to know what they were doing and/or what they were using... then you need to return to that office, and inquire there as to what they were using to achieve that set up. In essence what they were doing, was using a virtual device driver that was installed on the primary machine and laptop, that would push the device commands through that "cable" (could be network, who knows?). – Bon Gart Sep 2 '12 at 16:06

What they'll be doing is using the laptop to drive the external monitor, but setting the external monitor as the primary desktop, where the Windows taskbar/OS X menubar live.

What you want to do (using the desktop PC with the laptop screen as a secondary monitor) cannot be done, apart from perhaps using some extra software and a network. However, you might want to try running the desktop monitor from the laptop's display port, and then setting it to be the primary display for the laptop. The end effect will be the same.

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If I do this, where does the pc fit into all this? – Laptop Sep 2 '12 at 12:57
Well, it doesn't. But my thought was that it doesn't really matter whether you drive a monitor and a laptop screen with the laptop or the desktop PC, and it will certainly be much simpler. – wobytides Sep 2 '12 at 13:26

As an alternative, you may take another approach.
The approach is based on the principle that both desktop and laptop are running their own OS (and therefore, the applications). What you share is just a mouse and a keyboard.

There are many different solutions. I use Synergy since it is Free and Open Source.
There's also a tag .

Synergy Presentation

Although it is different to having two monitors on the same box, this approach reveals several interesting uses that can't be accomplished with a single dual-monitor system:

  • Keep personal things on a laptop and business (or performance-requiring) things on a desktop;
  • Learn (or just use) a different OS; I'm developing for Windows, but all personal stuff is on an Ubuntu-driven laptop. Both are running on same time;
  • It does not prevent you from using multiple-monitor solutions in the future: any of server/client machines may run as many monitors as they support;
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