Macbook not booting

[lauramar93]

So I have a Macbook Pro (several years old--sorry I can't remember how many exactly), that I have, in years past, upgraded with a new, larger hard drive and installed Snow Leopard on. Recently, I tried to do just a regular software update, iTunes included. When I tried to open iTunes, it said that that version could not open on the version of OS X I was using on my computer. So I went to try to upgrade to Lion, and tried to back up my computer to an external drive using Disk Utility, when it said that there were several items that needed repair, that I needed to open the computer using a different startup disk, repair the items, then back up the drive. But when I was looking up how to do that on the Apple website, they suggested starting up the computer in "Safe Mode" because I don't have another startup disk. (That entails holding down the shift key when booting the computer.) When I did that, AirPort was not working at all, so I decided to reboot the computer again. Now the computer has been stuck on the gray screen with the apple for about 30 minutes. What do I do?!

 

[wrldwzrd89]

After reading the description of your problem, it sounds like your MacBook has disk catalog structure damage. First thing to try when this happens is booting from your recovery media and run Disk Utility. This may be a DVD (for most Macs), a USB key (for older MacBook Airs), or the Recovery Partition Lion creates on the 2011 MacBook Air and Mac Mini. Anyway, once you're booted into the recovery software, follow the instructions to get to the utilities and choose Disk Utility. From here, select your Macintosh HD disk (unless you named it something else) and click Repair Disk on the First Aid tab.