There is some problem with my Nokia C7-00 since I upgraded to Symbian Anna. Problem is that some times (note it, sometimes, not always) I cannot change color of my display. It is stuck on White and bit cream. Also many a times its brightness gets lower though it is kept on high settings. I tried hard reset on the device but yet the problem exists the same. There is no good result. Do you guys have any idea about fixing these problems?