MacBook slow wakeup, black screen, Mavericks, took to Genius bar, worked OK for about a week and now the same.

Question

MacBook slow wakeup, black screen, Mavericks, took to Genius bar, worked OK for about a week and now the same.
Screen actually seems a very dark navy blue almost black. sometimes can see cursor in white
Only happens sometimes

Answer 1

If you can somehow document any processes you've put the MacBook
through, which can cause it to repeat the symptoms you've seen, be
sure to write down the sequence of events if your action and resulting
issues can be make re-occur. Then you'd have a fair chance at some
one looking deeper to find the real cause of this problem. {If you have
a digital camera handy, you can take a picture of the screen if it should
display some curious content other than a black screen, such as that
seen in a kernel panic or other message. Otherwise, a working Mac
can take its own screenshot.}
The computer should be returned to the Apple Store genius bar for
further evaluation & more in-depth diagnostic tests of long duration.
Sometimes a test may not run any of the additional software, together
or separately, that you may be accustomed to using. Perhaps the basic
OS X and a few applications work just fine.
If the issue is due to a conflict in software and not a hardware failure,
the cause may be harder to discover. If you have a complete backup
of the system and your files on an external drive, that may help if you
need to reinstall it. However if there is a problem in that software set
a new installation without conflicting software may be required in order
to troubleshoot the machine.
How old is the computer, how much RAM installed, how large a hard
disk drive and what is the remaining unused capacity of that drive?
(The HDD capacity will show 'other' so that may be unsubstantiated.)
Are there any indications in Activity Monitor, or in the system log files
from Console, to show crash logs or other effects from the Time/Date
of these slow wakeup and black-screen intervals? There may be.
Some of the system report may be helpful to those who know how to
read the resulting mass of files. Perhaps one of the more advanced
users who occasionally reply here will see your thread and offer a
method of accessing the OS X via Terminal or single user mode,
for troubleshooting purposes. Mine is an older OS X with less fuss.
Good luck & happy computing!
edited