Don`know what happens, when i turn on my iphone appears a lot of letters in my screen i have not time enough to read them becouse it does not stop appearing, and after 30 seconds it rebbots, and agein the same.
I have try all the thing i know, but the computer doesn't even tells that the iphone is conectted. I can not put it on DFU mode pressing the home and off button.
Have you tried recovery mode? Have it off, hold the home button, then while still holding, plug it into your cpu, keep holding home until iTunes and the USB plug show up...