So recently I have been noticing that there have been a lot of threads about how the OP's mac will not start up, or will just freeze when it gets to the grey apple. I believe it's time for one of my brilliant ideas: let's create a guide for these people. So, here is the steps I would take should this ever happen to me:
Pre-1: KEEP A BACK UP OF YOUR STUFF-too many times I've heard of people losing information-all of this can be avoided with an external HD and Time Machine
Obviously, if your mac won't even boot, you can ignore the steps that require it to boot lol.
1. Restart again-sometimes macs freeze on one boot, and sometimes this can be fixed by a simple restart. If you can't get to the login screen and therefore the restart button, hold down the power button until it restarts for a cold boot
2. Start in single user mode: Restart holding down command+S. Type "fsck -fy" (without quotes). This will perform a disk check and will tell you what is wrong with the HD. When this process completes, type "reboot" (again, without quotes) and your computer will restart
2. Restart from the OSX DVD: If you still can't get it to start up, pop in your OSX restore/install DVD and boot up from it holding down the C key. Then go to the Utilities Menu and choose Disk Utility. From there, hit "repair permissions"
3. Reset SMC: If the OSX DVD doesn't do anything, unplug the computer from AC power, take out the battery if it is a laptop, and hold down the power button for 20 seconds or so to drain all of the power. Then put the battery back in, plug the machine back in, and boot it up
4. Reset PRAM: If resetting the SMC still doesn't solve it, restart holding down command+option+P+R
5. Use DiskWarrior or Drive Genius 2/TDM Mode: If none of these has had any effect on your mac, it's time to try something a little more heavy duty. Enter DiskWarrior and Drive Genius 2. These programs will de-frag your directory and hopefully allow you to boot up again. Pick up a copy of one or both of these, pop in the disk, and boot from it by holding down the C key during the boot. Then select "repair" and follow the onscreen instructions. Another option is to start up in what's called Target Disk Mode (TDM). You will need another mac and a FireWire cable for this (sorry unibody macbook owners, this is not possible for you due to the lack of a FireWire port). Start up the other mac (not the one with the boot issue). Connect the two computers with the FireWire cable. Then boot the mac with the problem while holding down the T key until you see a FireWire symbol migrating around the screen. Your HD will now mount on the other mac, and you can run diagnostics from there.
6. Apple Store time: If none of these has had any effect, it's time to bring it in to an Apple Store and ask them to take a look at it.
I hope this has helped you solve your problem. Please feel free to add anything I may have forgotten.
Pre-1: KEEP A BACK UP OF YOUR STUFF-too many times I've heard of people losing information-all of this can be avoided with an external HD and Time Machine
Obviously, if your mac won't even boot, you can ignore the steps that require it to boot lol.
1. Restart again-sometimes macs freeze on one boot, and sometimes this can be fixed by a simple restart. If you can't get to the login screen and therefore the restart button, hold down the power button until it restarts for a cold boot
2. Start in single user mode: Restart holding down command+S. Type "fsck -fy" (without quotes). This will perform a disk check and will tell you what is wrong with the HD. When this process completes, type "reboot" (again, without quotes) and your computer will restart
2. Restart from the OSX DVD: If you still can't get it to start up, pop in your OSX restore/install DVD and boot up from it holding down the C key. Then go to the Utilities Menu and choose Disk Utility. From there, hit "repair permissions"
3. Reset SMC: If the OSX DVD doesn't do anything, unplug the computer from AC power, take out the battery if it is a laptop, and hold down the power button for 20 seconds or so to drain all of the power. Then put the battery back in, plug the machine back in, and boot it up
4. Reset PRAM: If resetting the SMC still doesn't solve it, restart holding down command+option+P+R
5. Use DiskWarrior or Drive Genius 2/TDM Mode: If none of these has had any effect on your mac, it's time to try something a little more heavy duty. Enter DiskWarrior and Drive Genius 2. These programs will de-frag your directory and hopefully allow you to boot up again. Pick up a copy of one or both of these, pop in the disk, and boot from it by holding down the C key during the boot. Then select "repair" and follow the onscreen instructions. Another option is to start up in what's called Target Disk Mode (TDM). You will need another mac and a FireWire cable for this (sorry unibody macbook owners, this is not possible for you due to the lack of a FireWire port). Start up the other mac (not the one with the boot issue). Connect the two computers with the FireWire cable. Then boot the mac with the problem while holding down the T key until you see a FireWire symbol migrating around the screen. Your HD will now mount on the other mac, and you can run diagnostics from there.
6. Apple Store time: If none of these has had any effect, it's time to bring it in to an Apple Store and ask them to take a look at it.
I hope this has helped you solve your problem. Please feel free to add anything I may have forgotten.