Well I was starting to write an essay rough draft on my brand new macbook and it started to moo...it wasn't horribly loud but it was definitely there. Anyways I just reset the PMU and it has been quiet so far...if the problem persists I guess I will be contacting applecare this week. According to my serial number my white macbook is from week 30. Despite the moo I am still really happy with my macbook that is replacing my 12" powerbook . There has been no other noise besides the moo (whine etc), and I guess time will tell if I get any discoloration on the case.