Computer won't fully boot in Yosemite 10.2.2

Question

Today I tried to start my MBP 15" Retina (early 2013) running OS X 10.2.2 and what happens is I get the apple logo and the white line below only moves to about 1/4 the distance and then hangs up. A few weeks ago the emergency boot disk disappeared and I can only access it with command-r on startup. So I booted from my CopyClone backup which has the emergency disk installed and ran Disk Utilities. No problem.
Yesterday I had some help from Apple for a problem with iTunes (which returned right after we finished, by the way). In order to do this I had to install their screen share utility. Each time when she asked me to reboot the computer it would get back to just the blank desktop picture and go no further. I had to force the restart by holding down the power button. That happened several times.
Then I noticed last night that twice it failed to go to sleep after the time set in the power settings. The screen saver came on. I again had to force a shutdown.
Since we were preparing for a storm to hit I just shut it down and unplugged it. This morning when I plugged it in and started it, the magic of the non-starting screen appeared. When I rebooted holding down the shift key I was able to start up, but the screen refreshed with white and gray bars before the actual computer screen appeared, and everything ran very slowly. I could not access the web by Safari. So I am using the CopyCLone disk to do this request for help. Please let me know what to do. I need this thing for work! Even if we do have a 1/2 inch of ice all over the outside! LOL

Answer 1

I think you should try the following.
Reinstalling OS X Without Erasing the Drive
Boot to the Recovery HD: Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
Reinstalling OS X Without Erasing the Drive
Repair the Hard Drive and Permissions: Upon startup select Disk Utility from the main menu. Repair the Hard Drive and Permissions as follows.
When the recovery menu appears select Disk Utility and press the Continue button. After Disk Utility loads select the Macintosh HD entry from the the left side list.  Click on the First Aid tab, then click on the Repair Disk button. If Disk Utility reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit Disk Utility and return to the main menu.
Reinstall OS X: Select Reinstall OS X and click on the Continue button.
Note: You will need an active Internet connection. I suggest using Ethernet if possible because it is three times faster than wireless.
Also see:
Reinstall OS X Without Erasing the Drive
Choose the version you have installed now:
OS X Yosemite- Reinstall OS X
     Note: You will need an active Internet connection. I suggest using Ethernet
                 if possible because it is three times faster than wireless.