Hi. Do the following to try and reset your Samsung Galaxy Centura (SCH-738C)
1. Press and hold the Volume Up together with the Power button at the same time
2. Release the Power button after one second but keep the Vol Up button held down until the Recovery Menu is displayed in blue
3. Scroll down using the Volume down button and highlight "Wipe data/ factory reset" - and select or confirm with the Power button.
4. Scroll to "Yes - wipe all user data" and select or confirm with the Power button.
5. With the Reboot now option highlighted, select or confirm with the Power button to restart the Galaxy Centura
After that the Centura S738cshould be reset to factory default requiring to be re-setup.