My Nexus 5 is Hard Bricked topic

"My Nexus phone runs on Android 5.0.1 and after this updtae the camera started to fail today the same happened after a quick reboot the camera runs as always. Today I had the same problem I pressed the power button and taped on "Turn off" the device turned off. Everything is OK now but then after I pressed the power button to turn on NOTHING happened nothing appeared on the screen, no vibration, no sound, NOTHING. I followed the steps on Google's video for this issue but it doesn't work. I tried "volume up+power, volume down+power, volume up+volume down+power" again nothing.
Then I plugged in the phone on the PC and again pressed the power button a sound came from the PC (like I plugged in a Flash Drive) and the Pc said driver installing failed. I switched to the other USB port again the sound appeared and the driver installing icon appeared (There is nothing on the phone screen) the driver to be installed is *QHSUSB_BULK* I have no idea what it is but I need my phone working.
Sorry for my misspellings and for my gramar mistakes but my native language is not english. If you could answer me with a easy english I would be glad."
This was my thread at The Google Support forums two months ago. I gave up after nothing worked. Yesterday I started my driverscanner program to install a driver after the scan there was a driver named "QHSUSB_BULK - Port_#0006.Hub_#0005" I installed the driver. Today I connected my phone to my PC. And windows update appeared with "Qualcomm HS-USB QDLoader" driver. It got installed then I did reasearch about it on the internet and I discovered that my phone got hard bricked. But Unfortunately a blackout happened in our appartment. After the blackout my PC couldn't recognize my phone and always says Unknown device I tried it on another PC but the same please help me what sould I do?
Sorry for my long thread.