black screen with broken lock button

My iphone 5 screen went black even though it was still charged, my lock button is broken so i cant do a hard restart. I did some research and i was told to erase iphone from find my iphone to get the screen to turn on. Icloud said my phone had been successfully erased but the screen never came on. Now my phone does not respond to anything except for when i plug it in to a computer and the computer makes a noise. the screen is also a little loose