Hi all, bit of a newbie here so forgive me if this has been covered somewhere, but I couldn't find it... I just got my macbook pro retina this morning which I got second hand. I was surprised that I didn't get the welcome screen when I got my 2009 mac pro (also second hand - previous user setup a new install for me). It went straight into the OS, although files are deleted, finder picks up old emails from the previous owner, one even had a password revealed (which is a nice reminder for everyone to wipe their computer properly in the future not just delete files and hope for the best!). Anyway, I would like to do a clean install to get that new owner experience. But how do I do this? There is no discs and all guides on the matter point at sticking in the disc for older mac's. Also - it has Lion installed, can I get mountain lion for free? I've not searched this yet but would hope so considering most retina pro's out there are running it.