Recently my jupyter notebook stopped launching. When I try the command jupyter notebook from anaconda prompt but it gives error
Traceback (most recent call last): File "C:\Users\Dell\anaconda3\Scripts\jupyter-notebook-script.py", line 6, in from notebook.notebookapp import main
File "C:\Users\Dell\anaconda3\lib\site-packages\notebook\notebookapp.py", line 51, in from zmq.eventloop import ioloop
File "C:\Users\Dell\anaconda3\lib\site-packages\zmq_init_.py", line 50, in from zmq import backend
File "C:\Users\Dell\anaconda3\lib\site-packages\zmq\backend_init_.py", line 40, in reraise(*exc_info)
File "C:\Users\Dell\anaconda3\lib\site-packages\zmq\utils\sixcerpt.py", line 34, in reraise raise value
File "C:\Users\Dell\anaconda3\lib\site-packages\zmq\backend_init_.py", line 27, in ns = select_backend(first)
File "C:\Users\Dell\anaconda3\lib\site-packages\zmq\backend\select.py", line 28, in select_backend mod = import(name, fromlist=public_api)
File "C:\Users\Dell\anaconda3\lib\site-packages\zmq\backend\cython_init.py", line 6, in from . import (constants, error, message, context,
ImportError: DLL load failed while importing error: The specified module could not be found.
I even tried reinstalling anaconda and upgraded to python 3.8.3 on windows 10 but still get the same error. When I tried to check jupyter notebook's version it said that ipykernel and some other things were not installed. jupyter --version gives me this:
jupyter core : 4.6.3
jupyter-notebook : 6.1.1
qtconsole : 4.7.6
ipython : 7.18.1
ipykernel : not installed
jupyter client : not installed
jupyter lab : not installed
nbconvert : 5.6.1
But installing ipykernel with conda install ipykernel says
All requested packages already installed.
I also tried ipython kernel install --name <env_name> --user but this gives another dll error.
Reading some other problems in stackoverflow I went and checked my enviroment variables.


Is there a problem with this environment variable. Please help.
Screenshot of the anaconda prompt with error.

Edit: The anaconda navigator does not launch either. anaconda-navigator on the anaconda prompt gives another error:

I also tried:
conda install qt --force
conda install pyqt --force
But that did'nt help. Does previously installed anaconda cause such error?