hello.. i have upgraded the mac to a 3,33 ghz hex cpu. After the installation the mac chimed but there was a blinking red light on the cpu tray , the computer closed itself after entering the OS.. it seemed like overheating so i made the heatsink more tight. Now the light blink a few seconds at boot time and stop.. the mac enter osx and seemed to be normal.. my question is it normal to have this red light blink a few seconds at boot ? i cant remember if it was there before.. thanks