My family's iMac (it's an older, white one) won't boot up all the way. When you turn it on the computer makes some clicking noises, and then a folder with a "?" on it appears over the blank white screen. The icon flashes in about 1 second increments and nothing else happens. It just does that till I tap the power button then it immediately turns off. I tried booting in safe mode, resetting PRAM, getting the drive chooser to come up so I could select Macintosh HD, but nothing happened when attempting any of those things. Does anyone have any ideas? I'm worried the HDD hit the end of the road. I'm not sure what the clicking sounds mean.