The Thinkwiki (for IBM/Levono laptops) site has useful information about graphics chipsets, which is often applicable to other laptops.
Note what it has to say about the Intel Integrated Video 950, which is consistent with the advice deano_ferrari has been providing you: Intel Graphics Media Accelerator 950 - ThinkWiki
and xrandr, and I quote:
External display with XRandR
Unfortunately, given all the radical changes to the Intel driver, and especially now with KMS, external display support has been rather in flux.
One of the issues encountered is that the maximum virtual screensize depending on driver version (or in the case of KMS, the kernel). This is important if you want to have an extended desktop (dual-display), but not for Mirror mode. If your using KMS, depending on what patches made it into the kernel the maximum virtual screensize is either 2048x2048 or 4096x4096. If your not using KMS, depending on the Intel driver version it will be either 1280x1280 or 2048x2048. 4096x4096 is not possible without KMS, and even then you might have to add this patch [Intel-gfx] [PATCH] drm/i915: Allow frame buffers up to 4096x4096 on 915/945 class hardware](http://lists.freedesktop.org/archives/intel-gfx/2009-July/003353.html) to your kernel to enable it.
To see what your virtual screensize is, simply run xrandr from a cmdline and look for something like this
Screen 0: minimum 320 x 200, current 1400 x 1050, maximum 4096 x 4096
As you can see in the above example the maximum virtual screensize is 4096x4096 which is ideal, and again, only possible in combination with KMS. If your getting 1280x1280 instead, your running an older Intel driver and have to add the Virtual line as shown below to your xorg.conf
Identifier "Default Screen"
Device "Intel Graphics Adapter"
Virtual 2048 2048
Once you have started X, you should find that your multiple monitors are automatically activated and mirror each other to the extent allowed by their potentially different geometries. If you want them to appear as a “large desktop”, you need to adjust their relative position with the XRandR utility. You can get an idea of what you’re working with by typing
This will give you a list of outputs and tell you which ones are connected. The external display port should be called “VGA” or “DVI” (or “VGA1” or “DVI1” in case of KMS) while the builtin LCD should be called “LVDS”. (or “LVDS1” in case of KMS). If, for example you want to stack your desktops vertically, you might do something like
xrandr --output LVDS --below VGA
xrandr --output VGA --below LVDS
your window manager may treat the two cases differently in terms of where it decides to put things like the toolbar. Ideally, you probably want to put the desired xrandr command someplace that it might get executed before your window manager starts. For example in your ~/.xsession or ~/.xinitrc file.
if you keep reading on that site you will see there is more provided.