Problem with opening Jupyter notebook

[problem solved] When I try to open jupyter notebook in cmd/power shell I get the following error:

Fatal error in launcher: Unable to create process using ‘“c:\users\NAME\appdata\local\programs\python\python39\python.exe” “C:\Users\NAME\AppData\Local\Programs\Python\Python39\Scripts\jupyter.exe” notebook’: The system cannot find the file specified.

I use the command “jupyter notebook“ and also “py -m jupyter notebook”. After searching about it and reading posts of other people with similar problems to mine, I tried reinstalling jupyter and then python but the problem persists.

I install jupyter with this command: “py -m pip install jupyter”

Also I HAVE python added to PATH and the command was successful in installing libraries such as pandas and matplotlib.

I have also tried to repair python using python installer, both before and after reinstallation.
Before the reinstallation it gave an error midway that I unfortunately didn’t copy but it was about not having access to a file called python.llb/ldb or something like that. (I am sorry but I really didn’t pay much attention at the time)
After I installed python again, the repair was successful. But I still get the same error when I try to open Jupiter.

For those interested, there’s discussion related to this on StackOverflow here.