My Samsung S4 mini doesn't start anymore. I put it on charge last night, and it was dead this morning. Holding down multiple buttons doesn't give me any repsond, not even vibrating. But when I plug it into my computer i can see a RELINK HS-USB QDLoader 9008 (COM6). If I can't fix the phone, I would at least like to try to save the data. Also, are there any other phones which use the same battery? That would make it easier to get hold of a battery to test if that's the problem.