Hi, I was wondering if anyone has any ideas on how I can trick Windows 8.1 into believing I have an additional monitor connected, so that it extends my desktop? The reason I want to do this is so that I can point some VNC client or whatever on my tablet (Win8) to that area and use it as a slow second screen while travelling. Any ideas?

You can Use Your Tablet As a Second Monitor, but it seems like you're looking more for a Remote Desktop kind of app.

Well, my tablet is a full Windows PC with a removable keyboard. So basically, I want to use one laptop as a screen for another. The first link is what I'm trying to do, except with Windows. There are plenty of remote desktop type apps, but in order for them to be useful, I need to make Windows think there's already another screen, otherwise I'll just get a mirrored screen. I want to extend my desktop to two screens so that I can drag applications and whatever to the second one (the tablet).

Will your tablet register the dragged app as an actual app that can be executed on a tablet, and not (remotely executing it from your tablet and making your desktop run the app)?

(Parentheses are used to circle the logic and prevent infallible logic due to punctuation.)

Synergy could be an even better solution for you - it won't let you extend your desktop per se, but it'll let you use your second computer as if it was a desktop extension, allowing you to seamlessly operate across the two while either runs on their own.

The whole point is that I want a bigger desktop for one computer. A typical scenario is that I have Visual Studio open. I want the main window with the editor on one screen, other windows such as Find references, unit tests and what not on the other screen so that they don't cover the editor. On my desktops, I have two monitors connected, and I also have a docking place-ish for my laptop at my office with two screens. When I'm travelling however, I don't want to carry an extra screen whereever I go. Instead, I want to install some app on my tablet/second laptop that just connects to my primary laptop and extends its desktop. In short, I have two laptops and I want one to act as a screen for the other one.

There are probably lots of ways to implement this. The solution that seems easiest to me would be to just fool my primary laptop into thinking it has a second screen, so that it allocates the backbuffer or whatever, even though there's nothing to display the contents. Then, I would use something like a VNC solution to connect my second laptop to my primary, and just use it to view the backbuffer of my "ghost screen". Maybe I can pretend that my second laptop (tablet) is a network projector and have my primary laptop connect to that.

I have no interest in controlling my primary laptop from my secondary one. We can also assume that both laptops are on the same network and can communicate with reasonably high bandwidth.

VNC should have a "virtual desktop" solution. At least, it does on *nix. I don't remember if it has virtual desktop support on Windows.

Bah, I should have read Servant of the Lords post more carefully. One of those solutions can actually use a Windows PC as a secondary screen, it just wasn't very clear from the articles and their own product page. They advertise it pretty much exclusively as an iOS app for some reason. Now let's just hope the Windows 8 drivers that are in beta state are stable enough.

Thank you everyone for your help and interest!

EDIT: Never mind, it doesn't work on Windows 8. At least not on my laptop. Still looking for solutions then. Dummy adapters, WiDi receivers, network projector receivers, anything..