Hi, I'm having trouble with my late 2008 mbp 15". It used to work perfectly then one day I shut it down and couldn't boot it up again. I removed the battery and held the power button for about 15 seconds and tried to boot it again and it worked. Now everytime I shut it down or it drains the battery I cannot reboot it unless I do the same thing over and over again until today where it couldn't be booted up like always no matter what I did. What could be the problem?