Help Locked= Reboot

[darkyei]

Hi there , I'm facing a problem with my sister's galaxy S3 and problem it's really too weird for me .I've done a lot and the problem still there.tried hard resetting and re-flashing different roms - it makes no difference.I've also tried factory reset , wipes and nothing.Even Stock Firmware has the same issue

If I'm using the phone it works pretty well and it can be hours , If I lock it does recover well but I leave it and it's locks by itselfs(3 seconds or so) it reboot! It's really too hard for me to understand what's happening because I can use it for hours and nothing happens.I'm too frustated and dont undertand what's happening

Check this video to see what I mean(with custom room) : https://www.dropbox.com/s/qfntfm6w8uuyync/videoGS3.mp4


Thanks!

 

[Rxpert83]

I'd you've restored the phone back to stock and its still having issues, its a hardware problem, and not a software one

Do you have insurance?

Is it still under warranty?

 

[darkyei]

I'd you've restored the phone back to stock and its still having issues, its a hardware problem, and not a software one

Do you have insurance?

Is it still under warranty?

Sadly not , the worst is that I bought it abroad and as Samsung's Support representative told me "if was not bought in the USA we can not do anything" .
So right now I don't know what to do.My only choise is going to a local "phone repairs" shop but I do really doubt that any of them would help me, any ideas?