My Iphone 5 Won't boot up or respond / ONLY DEAD

Hey everyone

I have an Iphone 5 that i have been boutgh for like 6 months ago. It worked perfectly during this time, until yesterday when it just died without any reason. The screen is just black, it dosen't respond to anything. When i connect it with my pc (Itunes) it dosent even reconiagze it. I've installed the latest version of Itunes, restarted my pc. But its just dead

I've tried many solution that some pepole tiped around here

I've tried the following "solutions"

• only holding the lock buttom at the top
• holding both the home and lock buttom together for like 5 min
• charching the phone in like 9 houres when i slep, the i tried the hard restart
• connetcing to pc and waiting the doing the hard restart

So please, whats the real solution ?