Every block in all versions have diapeard

I got on minecraft to get on to version 1.5.2, and got on a world I recently downloaded and got on it... every block but sings where invisible... I quickly change it to 1.6.4, still, everything but sings were invisible. 1.7.4, this time a different map.. still invisible... it deleted all texture packs and resource packs and still, invisible.