I tried to reintall os x mavericks but now is aking for apple id and pass w but dont have one what do i do?

Question

Hello I really need help, Im totally stuck!!
I tried to reintall os x mavericks  by following this steps:
Erase the hard drive:
  1. Select Disk Utility from the main menu and click on the Continue button.
  2. After DU loads select your startup volume (usually Macintosh HD) from the
      left side list. Click on the Erase tab in the DU main window.
  3. Set the format type to Mac OS Extended (Journaled.)Click on
      the Erase button and wait until the process has completed.
  4. Quit DU and return to the main menu.
lect Reinstall osx mavericks and click on the Install button
but now is asking for an apple id and pass word which i dont have. I know that the computer is a mid 2012 and according to apple rep the original software on computer was at least a 10.8 mountain lion but don't know how to retrieve since im not the original purchaser. What can i do to fix this problem? pls help!!

Answer 1

You will have to do the following which should install a copy of the original software pre-installed on the computer when it was new. You may then upgrade under your Apple ID.
Install Mavericks, Lion/Mountain Lion Using Internet Recovery
Be sure you backup your files to an external drive or second internal drive because the following procedure will remove everything from the hard drive.
Boot to the Internet Recovery HD:
Restart the computer and after the chime press and hold down the COMMAND-OPTION- R keys until a globe appears on the screen. Wait patiently - 15-20 minutes - until the Recovery main menu appears.
Partition and Format the hard drive:
1. Select Disk Utility from the main menu and click on the Continue button.
2. After DU loads select your external hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Partition button and wait until the process has completed. Quit DU and return to the main menu.
Reinstall Lion/Mountain Lion. Mavericks: Select Reinstall Lion/Mountain Lion, Mavericks and click on the Install button. Be sure to select the correct drive to use if you have more than one.
Note: You will need an active Internet connection. I suggest using Ethernet
            if possible because it is three times faster than wireless.