Broken iPhone 4?

Okay so my friend said his iPhone broke and I offered to fix it. I was only thinking that it needed a battery replaement,but I was wrong, I was messing around with it, and tried to enter DFU mode, which it did. I opened up iTunes which would only reconize the device in DFU and tried to restore. It would say "device has been put in recovery mode blah blah". So then eerything works fine. There is a few sounds that sound like a USB plugging in and out, and sometimes in Windows device manager, they do dissappear and reappear. Now it gets so a part that says something like "checking appl server for iphone restore" or somhing like that. Then for the first time, the device lights up with a dark gray background and then the disconnect/reconnect sound comes again.. it says at that same thing for a while and then says 1302 error. I have ttried everything to fix this. i dont know why the phone wont turn on and only lights up at the same spot, but does anyone have any ideas???? I can also enter pwned dfu mode but i cant enter recovery mode and even if i could, i probably wouldnt be able to see the connect to itunes sign. So yah, computer doesnt reconize it but itunes does when its in dfu mode. but doesnt display any info besides iphone 4. the rest is question marks..??