I cannot get pyqt5 to run under anaconda python

I cannot get pyqt5 to run under anaconda python. The following is an error message I get when I run a script shown below:

Traceback (most recent call last
File [full path to the python script], line 9, in <module>
from PyQt5.QtCore import QT_VERSION_STR
ImportError: DLL load failed while importing QtCore: The specified module could not be found.

Here's the script that produced the error shown above:

import sys
print("Python version:  " + str(sys.version))
print("Version info.:  " + str(sys.version_info))
print("sys.hexversion:  " + str(sys.hexversion))

from PyQt5.QtCore import QT_VERSION_STR
from PyQt5.pyqtconfig import Configuration

print("Qt version:", QT_VERSION_STR)
cfg = Configuration()
print("SIP version:", cfg.sip_version_str)
print("PyQt version:", cfg.pyqt_version_str)

I made the following attempts to fix the problem:

I added "C:\ProgramData\Anaconda3" to the path variable for my User Win10 Environment Variables, after reading: https://www.quora.com/How-can-I-fix-%E2%80%9CImportError-DLL-load-failed-The-specified-module-could-not-be-found%E2%80%9D-in-Python-3 A comment suggested, "Just add the Python base DLL location to your path variable and restart the interpreter shell or IDLE."
I verified that my "C:\ProgramData\Anaconda3" does include a python3.dll file

Here's my Python and PyQT5 installation info:

I installed everything as administrator
To install Anaconda: I ran Anaconda3-2020.07-Windows-x86 64.exe, downloaded 2020-08-30 07:21 PM
To install PyQt5: I was unable to run "conda install pyqt=3.8.6" The Anaconda prompt said that the package was not available.
So, instead, I ran: conda install -c anaconda pyqt, as recommended by https://anaconda.org/anaconda/pyqt
Then I ran "conda list", which reports that I have installed: "qt 5.9.7 vc14h73c81de_0 [vc14] anaconda"

But I still cannot run pyqt, because of the error shown at the top of this posting.
Any suggestions would be much appreciated.

Solution

I had a similar problem with PyQt - after upgrading to spyder 5.2.2 neither anaconda nor spyder would open at all - no splash screen etc or anything - it didn't even try to start the programs. Trying to start from the prompt, "anaconda-navigator" and "sypder" both returned:

(base) C:\Users\Geography Chair>spyder
Traceback (most recent call last):
  File "C:\Users\Geography Chair\anaconda3\Scripts\spyder-script.py", line 10, in <module>
    sys.exit(main())
  File "C:\Users\Geography Chair\anaconda3\lib\site-packages\spyder\app\start.py", line 233, in main
    from spyder.app import mainwindow
  File "C:\Users\Geography Chair\anaconda3\lib\site-packages\spyder\app\mainwindow.py", line 41, in <module>
    requirements.check_qt()
  File "C:\Users\Geography Chair\anaconda3\lib\site-packages\spyder\requirements.py", line 44, in check_qt
    import qtpy
  File "C:\Users\Geography Chair\anaconda3\lib\site-packages\qtpy\__init__.py", line 188, in <module>
    from PyQt5.QtCore import PYQT_VERSION_STR as PYQT_VERSION  # analysis:ignore
SystemError: initialization of QtCore failed without raising an exception

(base) C:\Users\Geography Chair>anaconda-navigator
Traceback (most recent call last):
  File "C:\Users\Geography Chair\anaconda3\Scripts\anaconda-navigator-script.py", line 6, in <module>
    from anaconda_navigator.app.main import main
  File "C:\Users\Geography Chair\anaconda3\lib\site-packages\anaconda_navigator\app\main.py", line 19, in <module>
    from anaconda_navigator.app.start import start_app
  File "C:\Users\Geography Chair\anaconda3\lib\site-packages\anaconda_navigator\app\start.py", line 15, in <module>
    from qtpy.QtCore import QCoreApplication, QEvent, QObject, Qt  # pylint: disable=no-name-in-module
  File "C:\Users\Geography Chair\anaconda3\lib\site-packages\qtpy\__init__.py", line 188, in <module>
    from PyQt5.QtCore import PYQT_VERSION_STR as PYQT_VERSION  # analysis:ignore
SystemError: initialization of QtCore failed without raising an exception

After a fair bit of messing around (conda install -c anaconda pyqt, conda install -c conda-forge pyqt, installs with specific versions...) I finally tried just updating pyqt (conda update pyqt). It worked. This is what it returned, if it helps anyone:

The following packages will be downloaded:

    package                    |            build
    ---------------------------|-----------------
    pyqt-5.9.2                 |   py38hd77b12b_6         3.3 MB
    sip-4.19.13                |   py38hd77b12b_0         261 KB
    ------------------------------------------------------------
                                           Total:         3.6 MB

The following packages will be REMOVED:

  ply-3.11-py38_0
  python_abi-3.8-2_cp38

The following packages will be UPDATED:

  ca-certificates    conda-forge::ca-certificates-2022.9.2~ --> pkgs/main::ca-certificates-2022.10.11-haa95532_0 None
  pyqt                  anaconda::pyqt-5.9.2-py38ha925a31_4 --> pkgs/main::pyqt-5.9.2-py38hd77b12b_6 None

The following packages will be SUPERSEDED by a higher-priority channel:

  certifi            conda-forge/noarch::certifi-2022.9.24~ --> pkgs/main/win-64::certifi-2022.9.24-py38haa95532_0 None
  conda              conda-forge::conda-22.9.0-py38haa244f~ --> pkgs/main::conda-22.9.0-py38haa95532_0 None
  openssl            conda-forge::openssl-1.1.1q-h8ffe710_0 --> pkgs/main::openssl-1.1.1q-h2bbff1b_0 None

The following packages will be DOWNGRADED:

  sip                                  6.6.2-py38hd77b12b_0 --> 4.19.13-py38hd77b12b_0 None