Minecraft blocks are invisible?

When i spawn into a new world in singleplayer mode it drops me in on top of invisible blocks, it appears as if i'm surrounded by the sky. The block outlines are visible but the blocks themselves are invisible. Any help with this would be greatly appreciated. I have a r7970 with latest drivers and the minecraft version is 1.7.4
thanks,
Will

Added (1). I've tried forcing the game to update but that didn't work… And I don't know where to find the texture files or how to repair them?

Try forcing the game to update. Maybe your texture file is corrupt?