how to list all installed modules

[harryos]

On Feb 18, 9:42 pm, Peter Otten <__pete... at web.de> wrote:
> >>> help("modules")

thanks Peter.That helped.
> Regarding the original problem, do you have multiple Python installations?
> If so, you may accidentally be running the "wrong" python.

I have only one installation.It shows all other modules.I will try
reinstalling .
regards,
harry