Recently people have been having trouble with Windows 7 & 8 relating to Advanced OpenGL. The fix is to turn it off. If you can launch Minecraft, go to options, video settings, and set Advanced OpenGL to false. If you can't launch Minecraft, i.e. black screen, stuck loading, Go %appdata% roaming minecraft options.txt (or whatever extension it may be) set AdvancedOpenGL so that it is false. This should also be done if you have an abnormally low fps as it makes it much easier on the CPU to generate terrain.
All people having trouble with Advanced OpenGL and rendering, this is how to fix.