Hi,
Sorry to hear about your phone. You can try to restart your device by press the OFF button on the backside and try to start it normally:
http://userguide.sonymobile.com/referrer.php?region=en&product=xperia-sp#Turning-on-or-off-the-devic...
Before doing this you may want to backup your information first. Check out this topic for more information on how to:
http://talk.sonymobile.com/t5/FAQ/Backup-amp-Transfer/m-p/407253#U407253
If the behavior persists, I would suggest that you repair the phone software using PC Companion:
http://www.sonymobile.com/update
In PC Companion, press start on Support Zone > Start on Update the phone/tablet software > Press the blue link that says "Repair phone/tablet".
