I have a samsung galaxy a3. My power button is working. i know this because if i hold it it will show me the option to turn off or restart. but if i just press it to make it sleep it wont turn off. i tried an app off google play to turn off my phone, but when i use it my phone will turn of for half a second and turn on at the lock screen. i need help, i have had this problem for a while now and im losing battery quick.