Since 1.6. my minecraft is buggy. when playing the screen flickers and showing me my background. i was playing on my friends 1.5.2 server and then he said: lets do survival games on 1.6 i updated it and shit started to go wrong. minecraft 1.6.2 is now unplayable for me becouse of the flickering.

can please someone help me

(tried to show it in a video where i TRY to rename a name tag but when i type something it says 'Name Tag' again.)

P.S. sorry if my english is bad