Is it possible to reformat/erase my original internal hard drive on Snow Leopard (10.68) working from my clone on an external hard drive *without* using the OS installation disks? I am just trying to erase and restore the original drive (which is running sluggishly and Disk Utility tells me it cannot be repaired so needs to be reformatted) but after several years have lost my install disks. I already successfully created a bootable clone on my external drive, but what is the next step to reformatting the original drive and restoring from the external clone? Can I just erase the internal drive and re-clone everything back from the external drive? I hate to have to pay for a replacement disk just to do this, especially when I'm probably going to upgrade to Snow Lion soon anyway. Any help would be appreciated!