iMac Dead - what to do next ?

[DeltaMac]

Now for the good part:
Disk Warrior may fix you up (maybe). It's a good tool, but isn't guaranteed to repair every situation.
Costs $100.
Replacing hard drive, as was mentioned above. You can get a new drive for less than $50.
Life is about keeping things in balance, I think.
(OP said Target Disk mode wouldn't work. Could be another result of a failed hard drive, eh? )

 

[Matt-London]

Thanks @DeltaMac - I've just downloaded disk warrior and using "disk warrior recovery" to create a flash drive.... fingers crossed !!