This procedure will erase all data stored in memory, installed apps, contacts (except those that are synchronized) depending on the model we have to act one way or another.
For this circumstance is the last option to try.
If we can work with mobile we can follow the following steps, otherwise we should adjust the following instructions of the manufacturers.
If your phone is not listed, please let us know by commenting this article you indicate to add.
Samsung Galaxy (all models):
With mobile off I hold down simultaneously: Volume + Home button and Power button until a logo appears on the screen.
In some terminals: With mobile off hold down simultaneously: Home button + Power Button
We will open a menu where you have to select the restart option factory system or wipe data / factory reset using keyboard volume up / down and select with the power button.
In the next menu you should select the one option that is not blank.
After this point the finishing operations and conduct a re-boot normally.
Sony Ericsson Xperia arc
We perform a cold start
Keeping pressing the left and right buttons on the screen
Press the power button
Do not stop pressing buttons until it vibrates the terminal or boot recovery menu.