Oh gosh this took me literally a FULL day to resolve yet so freaking stupid.
For those of you trying to run Python/Jupyter and get the annoying cmdlet not found error etc but you can start without issue, this is a pathing problem BUT an odd one. So…
Apparently you will need to add C:\ProgramData\Anaconda3 (for python) and C:\ProgramData\Anaconda3\Scripts and most importantly C:\ProgramData\Anaconda3\Library\bin (for Jupyter) for Powershell to recognize Python/Jupyter at the commandline level. I cannot believe this was not spelt out elsewhere… and I had to crawl StackExchange forever… Also not sure why even after reinstall Anaconda, it still did not path properly
Get http://patheditor2.codeplex.com/ to make it MUCH easier to work with… Best of luck.