Ubuntu 11.04 freezes on my GeForce 6600
I am running Ubuntu 11.04 Natty Narwhal. In previous versions it does not any problem, but now i cannot start any X Window Desktop except Safe Mode ( Bless a God ). It freezes few seconds after drawing Desktop Wall Picture, and free panels ( top, botton and left one new in Unity ). It start blinking of Caps Lock and Scroll Lock led indicators on keyboard.