Did you try resetting the SMC? The SMC could affect the following:
Fans
The computer's fans speed up quickly and remain at high speed.
The computer's fans run at high speed although the computer is not experiencing heavy usage and is properly ventilated.
Lights
The keyboard backlight appears to behave incorrectly (on Mac computers that have this feature).
The Status Indicator Light (SIL) appears to behave incorrectly (on Mac computers that have an SIL).
Battery indicator lights, if present, appear to behave incorrectly (on portables that use non-removable batteries).
The display backlight doesn't respond correctly to ambient light changes on Mac computers that have this feature.
Power
The computer doesn't respond to the power button when pressed.
A portable Mac doesn't appear to respond properly when you close or open the lid.
The computer sleeps or shuts down unexpectedly.
The battery does not appear to be charging properly.
The MagSafe power adaptor LED doesn't appear to indicate the correct activity.
System Performance
The computer is running unusually slowly although it is not experiencing abnormally high CPU utilization.
Video
A computer that supports target display mode does not switch into or out of target display mode as expected.
A computer that supports target display mode switches into or out of target display mode at unexpected times.
[URL|
http://support.apple.com/kb/HT3964?viewlocale=en_US]