Do a SMC Reset and while you're at it reset the PRAM. If you don't know how Google will do a quick find by typing in Intel iMac SMC Reset and/or Intel iMac PRAM Reset .
Do a SMC Reset and while you're at it reset the PRAM. If you don't know how Google will do a quick find by typing in Intel iMac SMC Reset and/or Intel iMac PRAM Reset .