Last night I shut down my intel 17 inch macbook pro (purchased about 2.5 years ago and I don't have much more information about the system) as normal...nothing out of the ordinary. However, when I went to boot up this morning to check my email, my computer unexpectedly shut back down with the apple logo and spinner on the screen. I tried to boot up in safe mode by holding shift with the same result. A friend suggested that I unplug it and take the battery out, hold the power button for 10 seconds, put the battery back in, plug it back in and then try to boot. Same result. I appreciate any help you could give me.