Phone

[BRAINZ2013]

To factory reset s3

http://www.hard-reset.com/samsung-galaxy-s3-hard-reset.html

 

[funkylogik]

If you have custom recovery, do the reset there. Not in the phone settings.
In settings it will wipe everything on the phone. In custom recovery just the data folder (apps mainly)

 

[shakib_787]

Thanks for the advice guys my phone hasnt turned off since I reset it

 

[shakib_787]

But ive realised it randomly locks on its own
Its quite unusuall

 

[BRAINZ2013]

Well if you did the factory reset correctly you should have to set up the device so if the screen Dont shut off u may want to set the display timeout . but is it shutting off like you started the post

 

[shakib_787]

No its not and ive sorted time oit and everything it will randomly lock