I am currently creating a 3D Facebook app with Unity with a main menu and a game stage from the tutorials friend smash offered by Unity and Facebook to get started with the API.
I would not consider myself experience with the unity engine and unaware of some features.
The game stage consists of terrain, a character and game objects.
To be clear these objects and every other texture ect is rendering perfectly on my home PC and a couple of others that I have tested it on which have both graphics cards and in-build graphics.
However on the other half of the computers I have tested it on (which by assumption only have inbuild graphics) I get either a completely black screen (objects are still there because I can still click where the play button is/press keys and get the sound feedback ect.) Or certain objects rendering as black. 
I am aware this could be because of the graphics capability of the computers however what is the best way to get around this? Is there a different type of rendering/lighting I could use to make them appear?
NOTE: Tried both fastest and fantastic build in rendering quality.
UPDATE: Tested on desktop publish with same effect on same incompatible computers.
Refer to screenshots below and any help greatly appreciated.
When first loaded the game - Completely black screen
After clicking where the play button is it brings me to the game stage with a non textured sheep and no sky box
After finishing go back to the main menu where some objects now appear including the sheep textures that were not appearing. - No sky box and no terrain testures
