Is there a program or utility that allows me to connect a touchscreen to my desktop PC and use it as a keyboard input device? My plan is to upgrade the screen on my laptop, pair the old screen with a touchscreen overlay and an inverter, connect it as another monitor to my desktop, and then lay it flat on my desk and use it for a keyboard.

I know that devices like the iPad have a virtual keyboard that is used to type on-screen, and my plan is to have a virtual keyboard like this running on the touchscreen all the time.

P.S. If there were any way to also use a portion of the touchscreen as a laptop-style touchpad, this would be very nice also. Thanks!
['https://superuser.com/questions/416967', 'https://superuser.com', 'https://superuser.com/users/130312/']
There are many [Virtual Keyboards](http://en.wikipedia.org/wiki/Virtual_keyboard) you could use for this purpose.

Some options:

* **Windows** has a built-in one called [On Screen Keyboard](http://windows.microsoft.com/en-us/windows7/Type-without-using-the-keyboard-On-Screen-Keyboard).
* **Mac OS X** can use a [Dashboard widget](http://www.apple.com/downloads/dashboard/reference/onscreenkeyboard.html). There may be a built-in one, but I'm unaware of it.
* **Linux** in general has many different programs, typically matching their desktop environments and often included as part of the distribution. A popular one for GNOME is [Florence](http://florence.sourceforge.net/english.html).
* Ubuntu, at least several versions ago, [came with one called onboard](https://www.combibo.net/articles/using_an_onscreen_keyboard_in_ubuntu/)

---

There is a (proposed) program called [Virtual Touchpad](http://code.google.com/p/virtual-touchpad/) that, funnily enough, allows you to use a virtual touchpad. Unfortunately, it looks like an abandoned project with no real work done. There is no shortage of phone or tablet applications that provide similar functionality, however, [as Lèse majesté points out](https://superuser.com/a/416992/117590).

The problem with trying to find such a program (aside from the utter rubbish that Google comes up with when searching for this) is most people tend to use a touchscreen directly, not with an indirect virtual touchpad. Of course, if you could get your OS to recognise your screen overlay as a tablet, that may help. It would probably make virtual keyboard use more difficult, however. (By tablet I mean the [input device](http://en.wikipedia.org/wiki/Graphics_tablet), not the underpowered computers/oversized phones.)
Bob's suggestion is probably best for keyboard, but if you want to use an Android touchscreen device as a mouse, you can use [RemoteDroid](http://remotedroid.net/) or [premotedroid](http://code.google.com/p/premotedroid/). Each requires a server app you run on your computer as well as the Android app client that you run on your phone/tablet.

As I understand it, you can only use the touchscreen as a laptop-style touchpad, not as an actual tablet device (i.e. you can't map the device to an area of the screen and draw on the tablet like a digitizer tablet), but you can at least use it as a mouse substitute.