I started to have trouble with my iMac and called up Apple to help me troubleshoot what was going wrong. Turned out that my internal harddrive was on its way to completely failing! They told me to back up what I could and turn it into one of the Apple stores or a certified repair shop to have them replace the drive for me, and since my AppleCare was up on it there would be a charge for the new drive, installation and the transferring of all my datta from the old one.
I was not about to pay a minimum of $300 to have another 320gb drive installed for me so I came to iFixIt.com and found all the info I needed to create enough confidence to believe I could do it my self at a fraction of the cost I would be charged to have it done. Not only that, but I would be upgrading from the original 320GB to a 2TB internal drive! I received my replacement drive and quickly started to get down to the nitty gritty job. The instructions provided by iFixIt were precise and easy to follow. After only 30 minutes I had pulled the old drive out and the new one in! Since I run TimeMachine back-ups on all my computers, I simply restarted my iMac using the system installation disc, used the disc utility to properly format the drive, installed the system software and restored all my info from my most recent back-up and 2.5 hours later everything was back to normal!
The only thing I can advise is to get one of the iFixit screw driver sets. I didn't and went to my local hardware store to pick up the star torque drivers I needed. When I told them what I was looking for they handed me a really nice set that was made for working on computers. I turned it over and immediately recognized the logo on the set.... It said iFixIt! The set worked great and made the job easy. I recommend buying the tool kit along with any other recommended things necessary to complete the job you are going to tackle. Having the right tools makes a huge difference in how the job goes. iFixIt will send you exactly what you need to make the job as easy as it can possibly be.