do you have the original OS X install disc that would have come with this MacBook?
Insert the OS X install CD.
Restart the computer and as soon as you hear the startup chime, press and hold the "C" key to boot from the disc. You can release the "C" when you see the Apple logo and progress indicator.
Choose your language and click to continue.
When you are sitting at the Introductory Installer screen (DO NOT INSTALL), go up to "Utilities" in the menubar and choose Disk Utility.
In the left hand sidebar, choose your Mac's hard drive (usually "Macintosh HD").
*If you do not see the drive, stop here and let me know what, if any, drives are listed.*
On the right hand side of the page, click "Repair Disk"
If it finds errors, repeat the process until it reports the drive is OK.
Next, click "Repair Disk Permissions"
Once the process has completed, choose “Disk Utility” > “Quit Disk Utility” in the menu bar at the top of the display.
Then, restart your Mac.
Restart the Mac
As soon as you hear the startup chime, press and hold the following keys;
COMMAND, OPTION, P, R
Hold them until you hear the chime a second time and then release the keys and allow the Mac to boot normally.
Now, repeat the prior procedure to boot from CD...
Shut off the Mac.
Plug in the power adapter to a power source, connecting it to the Mac if its not already connected.
On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
Release all the keys and the power button at the same time.
Press the power button to turn on the Mac.
Is there any change in how it boots?
you mentioned this MBP had not been running since 2014. Is that when it stopped working originally, or had it simply not been used and will not function now?
Ok, that would seem to indicate a software problem with the partitions on the drive...
Make sure the CD is still inserted in the MacBook.
Restart and immediately press and hold the OPTION key until the boot menu appears. Do you see the OS X Install disc?
Ok, since you have another Mac handy. My next suggestion would be to make an OS X installer on a flash drive and try re-installing OS X.
There's a pretty good guide here:
You will turn off the Macbook and insert the flash drive.
Then, hopefully, restart, immediately hold down the OPTION key and it will recognize the flash drive.
How far did you get?
It would seem there is something seriously wrong with the file system on the hard drive. I'm curious if it can be read at all.
There is a process that can be used to view the hard drive in one Mac on another as if it were an external drive. This is called Target Disk Mode.
In order to do this you would need a FireWire cable (possibly with a Thunderbolt adapter depending on models) to run between the two computers.
Make sure that both Mac's are turned off.
Make sure each is plugged into its AC power adapter.
Use a FireWire cable to connect the target (the sick Mac) to the host (the healthy Mac).
Turn the host on.
Start up your sick Mac and immediately press and hold down the T key until the FireWire icon appears.
The hard disk of your sick Mac should become available on the host. It should appear in the Finder as a mounted external drive.
If so, you made be able to use Disk Utility on the host to re-partition the drive properly.
Press the power button on your Mac to turn it off.
Unplug the FireWire cable.
Then use the flash drive installer to install OS X.
Ok, sounds good. If I'm not online at the time I will reply as soon as I see your response.
I'm sorry to hear that. I think, sadly, we are coming to the end of the road as far as what you can do as an end user to resolve this. Going off what you told me happened originally, this should not be an insurmountable problem. Normal recovery methods do not seem to be working that would not typically be failing just due to a software problem with drive partitions. However, I'm wondering if the keyboard on the Macbook is not entirely functional at this point as none of the key commands seem to have any effect. Do you have an external keyboard you might try using to repeat some of the prior steps?