Replacing hard drive in Macbook late 2009 what do I do about osx? I'm replacing the hard drive in my 2009 macbook (13" unibody). How do I go about installing OSX and can I go straight to Yosemite or do I have to install Mavericks and then upgrade? 
It's my first attempt at replacing a hard drive so I've no idea what to expect.
Thanks all!
You can use the drivers CD present in the MacBook box at the time of acquisition. Following the steps you can instal an old version and then update to the last one. Otherwise there should be the possibility of start a recovery and directly download (using a WiFi connection) the last versione of the OS.

An other option is to use Time Machine, if and only if, you have previously made a backup of the entire system before the swap of HD.