Android has a safe mode that you can get into. Simply starting this can wipe problems from you phone. Getting into safe mode depends on your handset, so it's best to Google the exact manufacturer, model plus the words 'safe mode' to find out the exact instructions. In General, though, you have to turn off the phone and remove the battery waiting for at least two minutes.
Press and hold the Menu button then press the power button.
Hold the Menu button the entire time until the phone has started and you should see the words Safe mode on the screen .
Power down the phone, take the battery out and wait for two minutes, then restart the phone.