Uninstall old python version(Python 3.9.7)

[Barry Scott]

> On 25 Dec 2021, at 06:13, Công Huy <cowsmile1911 at gmail.com> wrote:
> 
>   I had uninstalled Python 3.9.7 before but it wasn't uninstalled
>   completely. I found it still in my computer and when I click "uninstall",
>   it sent me a board "No Python 3.9 installation was detected". Of course,
>   it won't be an issue if it defaulted my main Python version on my computer
>   and I can't use some libraries I installed like numpy, matplotlib,
>   networkx,... To solve my python homework. I found some help on the
>   internet but it wasn't improved. I don't know how to fix it. Please help
>   me.

You seem to saying that you need 3.9, but you have removed it.
I'm guessing there is more going on then you have explained.
Otherwise simply reinstall python 3.9.

Barry

p.s. You signature contains an advert for outlook.
You might want to get rid of that.