my macbook charger is broken. i've managed to get it to charge but every time i touch a bit of the laptop that isn't one of the keys i'm getting an electric shock! ouch! thinking of ordering this http://www.amazon.co.uk/Replacement-Magsafe-Adapter-Charger-Macbook/dp/B007KSZMUS/ref=sr_1_1?ie=UTF8&qid=1381240889&sr=8-1&keywords=macbook+air+charger any advice?