Intenta quitarle la pila y asi dejalo por uan hora.
Volviendo al tema, haz un "soft reset":
If your PS Vita system has frozen during operation, shutting down and restarting the console should help.
First of all, try turning off the system.
Press and hold the power button for two seconds to turn off the system. You'll see an option to "Power Off", please tap this. If the system does not turn off or you can't see the "Power Off" option, press and hold the power button for more than 30 seconds until the screen turns off. After a moment, press and hold the power button for five seconds to turn on your system.
With PS Vita System Update v1.60 and later, you'll see a "Safe Mode" menu when your PS Vita restarts after being turned off in this way. It's completely normal for this screen to appear and you can restart your PS Vita normally by choosing option one.
Try updating the System Software.