Yes, you can turn off Cortana.
Yes, you can turn off Cortana.
You can modify the registry to achieve this. A guide is available at the provided link.
It seems unusual. Have you attempted to reboot your computer following any registry changes?
She still appears in system details, but it slows down performance and uses a large amount of memory.
The simplest method to turn off Cortana is using OOSU10. Keep in mind it can disable many features, including some critical ones, so avoid making changes if you're unsure about their effects.