I have a 2010 iMac, 27-inch, I7 2.93 processor, Snow Leopard. When I try to watch a DVD with either DVD player or VLC player the backgrounds are so dark I can't see anything. It happens on movies stored on the hard drive as well so it is not just a DVD issue. I have changed all the values I can find to adjust the picture, but nothing looks good. I can boot into Windows 7 on Boot Camp and the movies look great (very bright backgrounds and super clear). It has to be software or Windows on the same machine should look just as bad. Any ideas how I can fix this? The only reason I boot into Windows 7 now is to watch movies which is very annoying.