Power Up in Safe Mode - Samsung Galaxy™ Stratosphere™ II
Safe Mode puts your phone in a diagnostic state (returned to default settings) so you can determine if a third-party app is causing your device to freeze, reset or run slow.
With the device powered off, press and hold the Power button (located on the upper-right edge) for 3 seconds then release.
Shortly after releasing the Power button, the Samsung logo appears..
With the Samsung logo on the screen, press and hold the Volume down button (located on the left edge).
Continue to hold the Volume down button until "Safe mode" appears in the lower left of the unlock screen then release.
This may take up to 45 seconds.
With Safe Mode enabled, test device and app functionality. If the previous issue fails to occur, the cause has been isolated to a third-party app and all recently installed or updated apps should be uninstalled.
Power cycle the device to disable Safe Mode then reinstall and test each app one at a time to identify which app is causing the problem.