I just bought an macbook pro several weeks ago, it should be Mac OS X Lion, 10.8 I guess. This morning, after I press the power button, it keeps staying at a grey screen with an apple logo and a spinning progress disk, and refused to log in, I've been waiting for a long time. I forced to shut it down and use shift key and press power button again, it did not work, and I shut down again and with option key pressed and I start up again, and it did not work.
What should I do? Thanks
The first step is to narrow down which sequence your Mac is failing.
Sadly, that article links to an old archived version of how to troubleshoot startup issues. You'll want to start on Recovery boot to see if you can fix this hang or need to perhaps reinstall the OS.
In your case, the Apple logo and spinning gear means that the kernel was found but didn't finish setting up all the system resources. You could re-boot the Mac in verbose mode (hold Command-V at the start chime) to see exactly which part of the kernel /system is not progressing. You also will want to disconnect all peripherals just in case it's an external dependency failing. Usually, this step fails due to a hardware problem or the system needing a clean erase and reinstall (which you can do in recovery using Disk Utility to erase your drive and then re-download Mountain Lion).
