Try a SMC reset:
Power off holdleft side shift, control, option, and power up. Press these keys before the start up chime and hold them till the gear stops spinning.
Reboot
You can also try a PRAM reset:
Power down, hold option, command,P,R, (no commas) power up and hold these keys before the start up chime, continue to hold them till the start up chimes sounds again, then release.
Reboot
Yiu can also try a permisions repair:
Go>utilities>disk utilities, highlight your user disk (usually Mac HD or whatever you named it) click Repair Permissions.
All the best