Hi. I've been using my new Air for two weeks and i noticed lately that fan is always on, it's barely audible but still it's on. Even when laptop is cold, i open lid laptop turns on and fan goes on (but very quietly). I think when i just bought it i was surprised that it was off sometimes, i even showed it to my wife, "here, check this beauty, completely silent, like iPad". Is it me, may be i initially just didn't listen hard enough and it was supposed to be always on or something is wrong? I haven't installed anything new.