I have a Mid 2007 MacBook Pro 15in. Recently, the backlit keyboard has been flickering a lot. It seems like even the slightest change in light (even from adjusting the screen brightness) causes the lights to flicker. I used to use the backlight on full brightness, and my screen the same. So, this never was an issue for me. Right now, both are at top brightness, but if I slightly lower my screen brightness, the backlight on the keyboard freaks out. Before, it dimmed smoothly, but not anymore. What's wrong?