I recently bought a new mac mini (my first mac ever yay) with a 1TB hard drive at 5,400 rpm. the guy at microcenter also sold me a 1TB hard drive at 7,200 rpm and said it shouldn't be to hard to replace. He said first I'd need to back up the OS to a usb thumb drive and then physically replace the hard drive and then some how get the OS onto the new hard drive.
So far I've found a few tutorials online on how to physically replace the hard drive but it seems like a lot more work than I anticipated (ie. http://www.ifixit.com/Guide/Installing+Mac+Mini+Late+2012+Hard+Drive+Replacement/11716/1). Although, it does seem like something I could do.
However, my main difficulty now is i'm having a very hard time finding any help online on how to 'back the OS up on a usb thumb drive' and how I should re-install it once I do put in the new hard drive. He mentioned using time machine but when I open time machine it doesn't give me any options to interact with the USB thumb drive.
Best Answer
You could use Apple's OS X Recovery Disk Assistant to create a bootable recovery disk on a USB thumb drive. Since you've backed up to an external disk using Time Machine you could replace the hard drive, boot to the recovery disk on your thumb drive, use the recovery disk to format the hard drive and then reinstall 10.8/Mountain Lion. Once Mountain Lion is installed you will walk through the same setup procedure that occurred when you first bought your Mac. One of the first questions in the setup process is if you would like to restore information from Time Machine, which allows you to connect your Time Machine disk and restore your backup.