I have a 2.66GHz iMac running OSX 10.7.1. My monitor calibration is all whacked out. It won't let me change or calibrate in system preferences. None of the settings work. What can I do to reset them or fix this? When I go through the calibration assistant or select any of the other calibration profiles, it momentarily flashes to the selected change but then immediately back to what it is now (all whacked out).