Bear with me -- let me set this up. My mid-2008 model 24" intel iMac started making a horrible metal-on-metal scratching noise that is almost undoubtedly the hard drive going dead. It was a gift that did not include apple care. This means that the replacements aren't covered, but also means warranties aren't a concern. I decided to take it into the "geniuses" just for an official diagnosis -- the sound seems to indicate a dying hard drive, but I haven't had any freeze-ups or any malfunctions and the apple disk scanner doesn't come up with any problems. I had the hope that they would come back and say it's just a fan issue, I pay a hundred bucks and it's good to go. Unfortunately, they can't officially say one way or the other -- I don't know if it's wanting to get the extra money for exploratory surgery or what -- but the "genius" said it was probably the hard drive but could be a bearing in the hard drive fan. That doesn't help me much. Anyway -- I was thinking about replacing the hard drive anyway. I've been wanting to upgrade and this is as good a time as any to do it. I know my way pretty well around computers, and while admittedly my experiences are with PCs, I'm confident I can do this, especially with some of the good guides online. The "genius" talked about severe electrocution risk around the power supply. This doesn't seem to make much sense -- providing that the computer is unplugged and discharged -- and I haven't found anything online about it. However, I wanted to get some other opinions. Is this a reasonable warning? Or is it scare tactics? Should I go it my own, or find some other way?