Install the Nexus 5 drivers on your PC (just plug it in and wait a few minutes, it will install them automatically).
Ensure that you have Administrator rights on Windows (if you do not know what these are, you probably haven't got them).
Make sure your Nexus 5 has at least 60% of battery. 70% is better, and fully charged.. otherwise your phone may hung up.
Extras > Android Support Library, Google USB Driver\
II. Unlocking the bootloader
1. Turn off your Nexus 5. 2. Reboot into fastboot mode by pressing and holding the Volume Down + Power button. 3. Connect your Nexus 5 to your computer with a USB cable. 4. Open the Android SDK > SDK > Platform-Tools directory then right-click in an empty area while holding the shift key. 5. Click "Open the command prompt here". 6. Enter the following command:
If you get a serial number, it's good and you can continue. Otherwise, your drivers are not installed correctly.
7 . Enter the following command:
8 . On your Nexus 5, confirm with "Yes" using the Volume keys to move and the Power button to confirm.
9 . Enter the following command:
III. Installing the custom recovery
1. Turn off your Nexus 5
2. Reboot into fastboot mode (as in Section II)
3. Copy the custom recovery file downloaded earlier into the Android SDK > SDK > Platform-Tools directory. Rename the file "recovery.img". If it does not work, simply rename the file "recovery" without the "img".
4. In the command prompt window (as per Section II), enter the following command:
5. On your Nexus 5, use the unusable Volume buttons to select the "Restart bootloader" option and press the Power button.
6. You can now verify the custom recovery installation by entering "Recovery Mode". If you arrive on the CWM screen, the recovery is all good.
1 . Reboot your Nexus 5 normally. Copy the previously downloaded file "SuperSU v1.65" to the root of your smartphone.
2 . Reboot into fastboot mode (as in Section II) and choose Recovery Mode.