Plug it in using an original Nokia charger then use the reset key sequence.
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Reset my Windows Phone 8.1 | Windows Phone How-to (United States)
Press and hold the Volume down Volume down button and Power Power button buttons at the same time until you feel a vibration (about 10–15 seconds).
When you feel the vibration, immediately press and hold the Volume down Volume down button button until you see a large exclamation mark.
Once the exclamation mark appears, press the following four buttons in this order: Volume up Volume up button, Volume down Volume down button, Power Power button, Volume down Volume down button. Your phone should now reset and restart itself. (It might take a while for the reset to finish.)