Well, as AIJensen said, that's the best way to pass your HDD contents from one PS3 to another one.
I can help you with the formatting though, there's a software way to do it on your PS3, here's how:
First you'll have to have your PS3 lit up, then hold the power button until it shuts down. Next press the power button and keep it pressed until you hear three simultanious beeps and let go of the power button.
Your PS3 should open an BIOS OS menu in which you'll have many options, being one of them an option to do an Hard Format to your HDD.
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