Wolfshadw :
Yes, the laptop manufacturers get the drivers from the graphic card manufacturers, but they also tweak those drivers to limit their functionality so the graphic cards operate within the thermal designs and power limitations of the laptop. Installing drivers directly from AMD or NVidia will often cause blue screens or system freezes/shut downs.
-Wolf sends
Clearly Wolf I dont think you know what you are talking about. AMD and Nvidia have a separate option for those who own a laptop card vs a desktop card hence they label it when you are browsing through their download/support page. And clearly for the HD 4200 AMD has updated that so many times along with the rest of the HD lines. If you even patch notes AMD clearly states in every single release which GPU it supports including mobile versions.
And if you go the website i gave to the asker, it clearly states the different lines of GPUs it supports including Mobilitiy version of HD 4200. AMD tends to use the same drivers on the desktop and laptop cards.
Also No. Because for the reason I listed and its already there, using drivers from Nvida or AMD will not create problems and certianly none from my experience with a 8400GS mobilty card from Nvidia. It plays games and all the stuff i need without ever crashing. In fact using manufacturers website for your GPU will actually crash the GPU as they are too lazy to even update the drivers for newer applications.