hello , i just purchased the MBA 11.6'' 2012 128gb 8gb 1,7 and i have two questions. 1) i have 99gb left. 28 gb for what? is there an office suite installed? i think from the store they told me that it is preinstalled but i don't find anything. 2) the battery was about 80% when opened it . should i make a good full charge ? i have spend most of it. should i drain all the battery and leave it all night charging?