Can't play on any worlds

The launcher works fine, and I can access the main menu and sub-menu's, however trying to load a world results in a completely black screen, then a 'Steve' hand appear in the middle of the screen after about 5 minutes, and after around 10 minutes i get a corrupted blue sky with grey polygons/triangles. The same thing happens with any servers i try to load. Sometimes i get parts of the blocks around me appear but this is rare. The log cites this as a 'game crash'(attachment)
(I have had to put 1.8 as the Minecraft version as I cannot put 1.7.10, but i'm sure 1.8 is affected by this too)