My 2010 MBP has a periodic clicking noise, seemingly in the very front right corner by the pad. I know this is the location of the HDD, and have heard that the noise could be because it could be failing. However, the noise seems the worst only when I first start up my Mac. Once it's been going for a few minutes, it seems to subside mostly. I do shut my mac down nightly and regularly, as I generally don't use it daily, if that makes any difference. Should I be very concerned, since the clicking is mostly during the first few minutes of use after start up?