Hello, Due to sound cutting in and out the 'Genius' decided that my whole logic board needs replacing which is fine as it comes out of their pocket.... But my issue is what is the best way to back up my mac book seeing as I am reading horror stories from Time Machine? I have taken my laptop home to back it up so I can drop it off after it has been backed up sufficiently. I don't have an external hard drive with me at present - will i need to get one? What needs to be backed up? (folders? whole drives? apps?) What is wiped from computer? What is the most effective/safest way to do this? What will happen after the new logic board is installed? As much information in the simplest form would be greatly appreciated.