Why has my galaxy s4 reset itself? Also locked me out?!

[Android Central Question]

Hi, I have a samsung galaxy s4. I left my phone at home today and roughly 7 hours later I come to find my phone has somehow reset itself?! Its got the "life companion wallpaper, sound on (I usually keep it on mute)... Even worse, there's a pattern lock and backup pin set on it. I tried entering both I set for it but its not accepting either of them. What on earth do I do here? Have I lost everything on my phone now?! How do i get back into my phone now?!

PLEASE HELP!

 

[Rukbat]

Assuming that no one reset the pattern to prank you, the phone evidently went bad for some reason.

If you can't get into it, try changing the password by using Android Device Manager. Reset it, then wait 24 hours (that's in case someone got your password and asked the site to change it - you get 24 hours to say "no, that wasn't me"), then use the new password to unlock it. If that works, reset it to the way you like it, your pattern, your PIN. If it doesn't, the phone went bad. You can still try to boot into download (Volume Down/Home/Power) and reflash the ROM. Yes, you'll lose anything you haven't backed up or synced. but at least you'll be able to use the phone. (See [Samsung] How to flash Stock ROM via ODIN. Samsungs are easy to reflash, just boring. The phone can take 15 minutes to set up after you flash it.)