Instead of wiping my hard drive, my MacBook Pro is installing OS X. How do I abort this?

We need to know what you did and why. We need to know what version of OS X is involved. Why do you want to abort?

Press and hold down the Power button for about 5-10 seconds until the computer shuts down. Then:

Booting From An OS X Installer Disc

1. Insert OS X Installer Disc into the optical drive.

2. Restart the computer.

3. Immediately after the chime press and hold down the "C" key.

4. Release the key when the spinning gear below the dark gray Apple logo appears.

5. Wait for installer to finish loading.

Prepare Your Mac for Sale

Boot from the OS X Installer Disc One that came with the computer. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu. After DU loads select the startup volume from the left side list then click on the Erase tab. Set the format type to Mac OS Extended (Journaled) then click on the Options button. Select the one pass Zero Data option and click on the OK button. Then click on the Erase button.

Note: You can skip the Zero Data option if you are not concerned about removing sensitive personal data from the hard drive. If you choose to skip this part of the process then it is possible for others to recover data from the hard drive. The Zero Data procedure will prevent others from getting access to your personal information.

This process will take 30 minutes to several hours depending upon the size of the hard drive. After formatting has completed quit DU and return to the installer. Now complete the OS X installation. At the completion of the installation do not restart the computer. Instead just shut it off. The next user will be presented with the Setup Assistant when they turn on the computer just as it would if new out of the box.

That will only occur if you are trying to install pre-bundled software other than the OS. If you boot from Disc One and only install OS X per instructions, there should be no request for Disc Two.

In any event you can simply quit by shutting down.

Then eject the first disc if it's still in the drive, insert the second disc, then restart:

Five ways to eject a stuck CD or DVD from the optical drive

Ejecting the stuck disc can usually be done in one of the following ways:

1. Restart the computer and after the chime press and hold down the left mouse button until the disc ejects.

2. Press the Eject button on your keyboard.

3. Click on the Eject button in the menubar.

4. Press COMMAND-E.

5. If none of the above work try this: Open the Terminal application in your Utilities folder. At the prompt enter or paste the following:

/usr/bin/drutil eject

If this fails then try this:

Boot the computer into Single-user Mode. At the prompt enter the same command as used above. To restart the computer enter "reboot" at the prompt without quotes.

Did Disc One not eject automatically?

I'm not sure what you did precisely, but what you describe should not happen. To reiterate:

Booting From An OS X Installer Disc

1. Insert OS X Installer Disc into the optical drive.

2. Restart the computer.

3. Immediately after the chime press and hold down the "C" key.

4. Release the key when the spinning gear below the dark gray Apple logo appears.

5. Wait for installer to finish loading.

After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu. After DU loads select the startup volume from the left side list then click on the Erase tab. Set the format type to Mac OS Extended (Journaled) then click on the Options button. Select the one pass Zero Data option and click on the OK button. Then click on the Erase button.

Note: You can skip the Zero Data option if you are not concerned about removing sensitive personal data from the hard drive. If you choose to skip this part of the process then it is possible for others to recover data from the hard drive. The Zero Data procedure will prevent others from getting access to your personal information.

This process will take 30 minutes to several hours depending upon the size of the hard drive. After formatting has completed quit DU and return to the installer. Now complete the OS X installation. At the completion of the installation do not restart the computer. Instead just shut it off. The next user will be presented with the Setup Assistant when they turn on the computer just as it would if new out of the box.