Ok, so I have an Aluminum 20" 2.4 iMac. The other night, we had some pretty bad storms while I was asleep, and I think the power went out for a few seconds, or there was a surge. When I got up, my iMac would boot, but hang on the gray scree, every time. I DO have it plugged into a very capable surge protector. I called Apple Support, and after a little while of testing different key combinations, the lady told me to take it into the store, or they would send someone to my house. I took it to the store, where the genius did the exact same stuff that I did while I had the lady on the phone. The genius ordered a hard drive, as well as a logic board. I'm hoping that the logic board is what needs to be replaced, but I'm not sure. Do you guys know what the problem could be? I really don't want to lose any of my data on that hard drive. I had an external hard drive connected, with all of my music and pictures backed up, but none of my Windows machines will recognize it. They do that chime when it's plugged in, but it doesn't show up in My Computer. Any ideas?