How to Install Mountain Lion on Mac?

Installing Mountain Lion: What you Need to Know

You simply launch the Mac App Store application, click the OS X Mountain Lion banner on the stores main page or search for Mountain Lion, or click this direct link, click the $19.99 button at the top of the screen, then click the Buy App button that appears.

How do I Reinstall OS X Mountain Lion?

Reinstalling Mountain Lion
Restart your computer, and immediately hold down commandr until the gray Apple logo appears. If prompted, select your main language and then click the arrow. Click Reinstall OS X, and then Continue. Follow the instructions on the screen, and then choose your hard disk.

How do I Reinstall OS X Mountain Lion Without Disk?

Boot to the Recovery Volume command R on a restart or hold down the option key during a restart and select Recovery Volume. Run Disk Utility Verify/Repair and Repair Permissions until you get no errors. Then reinstall the OS.

How do I Factory Reset my Mac OS X Lion?

OS X 10.7 LION OR LATER
Restart your Mac and hold down the Command + R keys until the Apple logo appears. From there, youll see an OS X Utilities window with the aforementioned options listed. Select Disk Utility and erase your HD, just as instructed to do in the first section of this article.

How do I do a Clean Install of OS X Lion?

Gather the Essentials.
Prepare the Disk or Partition.
Perform a Backup.
Format the Destination Drive.
Use the Lion Installer.
Use the Setup Assistant.
Use the Migration Assistant.
Complete the Registration.