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Delete everything entirely and reset it back to factory?

Settings -> General -> Reset -> Erase all content and settings.

Hope this helps!
 
Plug it into iTunes and Restore, but instead of using a backup, set it up as new.
 
Delete everything entirely and reset it back to factory?

Settings -> General -> Reset -> Erase all content and settings.

Hope this helps!

Plug it into iTunes and Restore, but instead of using a backup, set it up as new.

You can go to Settings -> General -> Reset -> All contents and settings. That'll delete everything from your phone.

i wanted to remove the current OS then put the newest on...don't i do that by holding down some buttons?
 
i wanted to remove the current OS then put the newest on...don't i do that by holding down some buttons?

You're thinking of getting the iPhone into DFU or recovery modes, which is sometimes necessary if your phone is having software problems, or is jailbroken. But if your phone is working fine and isn't jailbroken, then all you have to do is "erase all settings" or restore from iTunes and setup as new.
 
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