Nothing works on turning on an iPhone 4s

here are the things Ive tried and the details on what happen:

-doesn't show if it's charging

-DFU doesn't work, holding home button and power buttotn for 30 secs(although when i do this while connected to itunes my pc makes a sound that its connected and update shows)

-connects to iTunes but doesn't show anything on screen

-tried to update but doesn't finish just showed apple logo for a couple of seconds and then gone again

-showed error 4005 on 1st update then error 9 on the next

-changed cable but still the same

-changed computer mac, windows

-friend's iPhone 4s battery transferred to mine but doesn't show anything

-my battery transferred to his it showed that it has 70% battery it means its charging

help :( is it dead? nothing else i can do ?