How to recover my harddrive if I can't see it in the disk utility I have a 2007 aluminium iMac which I upgraded months ago to Mavericks.
Today it locked up and I held the power button to shut it down and cannot get it to start again.
I get the flashing folder ? icon on boot which I understand means the boot drive is not found.


I tried Safe Mode (Shift after the boot sound) : nothing happened (grey screen)
I tried Single User mode (cmd+S after boot sound) : nothing happened
I tried recovery mode (cmd+R after the boot sound) : nothing
I tried booting with the option key, nothing.
I tried target disk mode with cmd+T, and it seemed to work in that it showed a different icon. However, I realized that I can't connect my new 2013 macbook to it because the latter does not have a firewire port (is there another way)
I also tried disconnecting everything, including the keyboard and mouse (I have bt keyboard and a usb one so I tried both, plus mouse and trackpad, tried both)
I tried reseting the PRAM and that other reset (where you unplug for 15s)
Finally I scrounged out my old installation disk (Leopard) and booted Installation disk 1.
When it came up, I went to Utilities in the menu and selected Disk Utility.


So far so good, but Disk Utility does not show my internal HDD, so I can't verify or repair it.
It does show my time machine drive connected by firewire, and of course it shows the DVD installation disk.

What do I try next?
Given this happened the way it did if there is disk corruption I think it should be minor and reparable. But right now I don't even know if I'd be able to restore a new OS.
Sorry Rhubarb but the next step is to physically remove the hard drive from the iMac. If you are not comfortable then the best option is to go to an Apple Store or Authorized repair center and let them do it for you.

They might even be able to test the iMac, hard drive cable, and the hard drive for you. Best case the cable just crapped out. Worst case the drive is dead and recovery is not possible. There are dozens of things in between both of those but more can be said concretely once the drive has been removed and tested in another enclosure.