brand new macbook air drops wi-fi connectivity randomly
i just bought macbook air last week, and it suddenly drops wi-fi connectivity on a regular basis. i try to fix it through network, but nothing i do in particular works; it seems that it reconnects itself randomly. how do i fix this? (when i try to go through network diagnostics and assistant, it displays erratic answers—sometimes it doesn't recognize the correct password for the wi-fi network, for example.) this symptom is really detrimental and i feel really frustrated.
MacBook Air, OS X Mountain Lion (10.8.4), 8GB 1600MHz DDR3