I have a Macbook, and it was running slow and wouldn't go away after I force quit the affected applications. So I tried to restart - and it didn't do anything. So I held the power button down. Then when I tried to reboot it, the gray screen comes up (without the apple logo or the little spinny thing) and just stays there. Nothing happens. Except the fan goes on. Ive tried rebooting multiple times... Even holding the power button down for 10 seconds until the tone doesnt work. Any help would be much appreciated. Thanks.