Just start your Mac holding Command, Option (Alt) and R keys, and reinstall OS X. Your Mac comes with OS X Recovery, so you don't need OS X Mountain Lion on a USB drive. Instead, it would be much better to get an external drive. In the case of Macs, I don't recommend you to install a hard drive bigger than 2 TB in order to avoid some problems. The following items are also compatible with this product. Any 2'5' SATA hard drive will work with your MacBook Pro, and you have three hard drive types: a 5400 rpm HDD, a 7200 rpm HDD and a SSD, choosing the one you most like (if you haven't got enough money for a SSD, go for the 7200 rpm HDD). MacBookPro8,3 - A1297 - EMC 2564 Late 2011 17-inch : How to find Model ID Installation videos: Standard Memory: 4 GB: Maximum Memory: 16 GB: Note: 4 GB of RAM is installed as two 2 GB modules, no slots free. Respecting to the hard drive, you can upgrade it or install a SSD without voiding warranty. You can buy more memory from OWC or Crucial. In fact, the 2011 MacBook Pro supports 16 GB of RAM.

Ram memory for macbook pro late 2011