If you are referring to 'completely' resetting up the device, that would mean a reset of the device. So anything you have personally added to it, files, music, apps, settings changes, contacts, etc., would be lost.
However if you haven't added much, then it would be worth it.
NOTE: Doing this will clear 'all' the data on your phone, so it is suggested you not choose this option unless you have to, or aren't worried about losing anything on the phone.
Be sure you back up any data you want to keep, to a computer or cloud account, before doing the reset.
To "Hard Reset" the phone...
1. Make sure that the phone is actually powered off.
2. Remove your SD card, if there is one in the device.
3. Press the "Power" and the "Volume Up"...