Open Question: What can I do to prevent PayPal scam on this transaction?

Okay please read this before you answer! I'm selling my Macbook on Craigslist. There's someone from out of state that wants to buy it and pay through PayPal. Here's my concern ... they may send me the money on PayPal, I ship it to them, they receive the laptop and then file a dispute that it doesn't work or something and get all their money back and KEEP the laptop (the laptop works perfectly). How can I ensure that I will not be scammed? I need to make sure that PayPal has proof that my laptop works and that I sent it in case he files a claim or something. What should I do to prepare for that? Also - if he does file a claim, will I be notified and able to make a counter argument before they rip the funds out of my account? Thanks guys!