Computer does not detect my device

[AC Question]

Even when usb debugging is enabled, my device does not provide authorized access to the computer.
I am trying to root using NRT v2.1.0 but it says ' adb device detected but not authorized'.
I reinstalled the drivers but now even the computer fails to detect the device. Please help!!

Thanks in advance!

P.S - My nexus 5 is running on android 6.0.1, build number - MMB29k