Hello, I have an Imac 9,1 (which I believe is early 2009 model) and I am running out of hard drive space on the original Hitachi 320gb drive. I am wondering whether this Imac has the issue with heat sensor cable and fan running full speed? Do I need to buy a certain brand of hard drive or replacement cable to avoid this occurring, or does this issue only affect newer Imac models? I have never opened up a mac before and deliberating whether it is even worth the risk. However the cost to have it professionally replaced is a lot!!! I have found a step by step guide on ifixit.com Thanks.