I am trying to open the game, after updating to the latest version, and it gets through the MOJANG and white Minecraft loading screen as previously, with no problems. Then it gets to the 'play game' page, and this is where nothing happens. The beautiful scrolling nether images show as usual, but then the option to open game etc do not, even after leaving to open for over half an hour. The only thing showing is a weird grey/white/black mark on the screen as seen on the screen grab.