Blank Black Screen

Are you sure you did the NVRAM reset steps correct?

Immediately when the startup chime sounds press and hold down Command + Option (Alt) + P + R keys. Keep all the keys held until the startup chime sounds a second time. If the startup chime does not sound twice, the NVRAM reset was not completed. You will need to restart the computer then try again until you hear a total of two chimes.

How to Reset NVRAM on your Mac - Apple Support

If you can hear sounds from the computer but do not see anything on the screen the issue is usually caused by a corrupt screen brightness setting that is stored in the NVRAM. Following the steps to reset the NVRAM should fix it. If successfully resetting the NVRAM does not resolve the issue attempt an SMC reset. If the issue persists you will want to take the computer to an Apple Retail Store or Apple Authorized Service Provider.

All: I tried all of the solutions in this thread and many others. I finally decided to call Apple Care...(even though my iMac is out of warranty). I was on the phone for maybe 10 minutes and my problem was resolved.

Apple is investigating the issue and its causes and said that they will assist ANYONE who calls in with this issue (whether your Mac is in warranty or not).

They had me go into single user mode and after a couple short commands I was back in business. (Sorry, I do not remember the commands)

The gentlemen I spoke to was a senior advisor (Shane Boyle) and he even asked that I reply to a couple of the threads informing people that they can call for assistance even if your mac is out of warranty. He was very pleasant to talk to and very knowledgable. Thanks Shane!

I had this same problem. I ran through all the forum support solutions....SMC reset, safe mode etc. No resolve. I looked for help on YouTube and this worked for me:

Turn the computer off.

Turn the computer on.

Don't touch any keys.

Once you see the cursor type the first letter of your Username.

Hit enter.

Type your password.

Hit enter.

Paradise.

Everything is back to normal.

Hope this works for you too.

Hi Kappy

I'm experiencing the same problem with my MBP only 4 months old.

I did the cmd r and a voice said "if you want to use english as your language, press return key" which I did. Now nothing.

Can you help me?

Resetting your Mac's PRAM and NVRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

Boot into Safe Mode then reboot normally.

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.

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 indented 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 and more reliable.

If you have a monitor available, connect the MBP to it. If an image appears, then the display connection or the display is faulty. Id the monitor is black, then the GPU is the problem.

Ciao.

Did you proceed to the other steps. You may need to reinstall OS X assuming it's not a hardware problem such as a failed HDD or SSD.

Your problem is not the same from your description, so I suggest you post your own separate topic.