Try this and see if it works (it did for me):
Boot your MacBook in safe mode (immediately after you hear the startup tone, hold the Shift key), and remove the file below and then reboot:
/System/Library/Extensions/ATIRadeonX1000.kext
You should know that this is not a permanent solution, as you loose some functions on your Mac, but at least you should be able to use your computer without any display anomalies.