So i have purchased the 2.7 GHz i5 27" iMac, i got it about 3 weeks ago, everything seems to be fine with it apart from the HD, if i am watching a movie on it at night and put it to sleep with the remote or if it just naturally goes to sleep from not being used the hard drive will boot up randomly and make quit a lot of noise for about 5 seconds and then just click and completely shut off, this will continue to happen until i physically turn the machine off. This won't happen all the time but about 50% of the time it will. I know that sound from hard drives is them in the first stages of failing, but i was wondering if there was anyone who has had this issue before or if there is a fix for it without having to return the mac, there is no Apple store close to me either. Thanks in advance for your replies.