A few days ago I bought a new iMac (last generation, with the optical drive). It was discounted since the new, thinner one is out. Well, I've decided to return it and go for the new one. But, I have loaded some stuff to it, now I need to erase/delete everything and return it to the new in box settings. Can someone please help? I have searched for answers on the board, but most answers say to insert the software disc and go to disc utilities...I never got a software disc and right now I'm erasing usable space on the hard drive, but it says it will take 13 hours and I still don't know if that's going to remove everything I've installed and uploaded.