Hi, I've recently installed an SSD drive on my late-2008 MacBook Pro, running Mountain Lion... and I'd like to install Mavericks, instead of jumping directly to Yosemite, at least for a while. A friend of mine gave me a bootable pen drive and... ehm... I kinda need a little help, since I've never done it! I remember I have to restart the machine, with the flash drive plugged in, and hold down the Option key until the boot menu is shown. What I want to know is... can I do an upgrade, maintaining all my settings, programs, data, etc... or is it only possible to do a clean installation that will wipe away everything? (I do have a backup, done with carbon copy cloner, but still...) Thanks fon any help you can give me! A'