How do I reinstall Kali Linux?

First, plug the USB drive into the respective computer that Kali should be installed upon and proceed to boot to the USB drive. Upon successful booting to the USB drive, the user will be presented with the following screen and should proceed with the ‘Install’ or ‘Graphical Install’ options.

Can I install Linux without losing data?

You should install Ubuntu on a separate partition so that you won’t lose any data. The most important thing is you should create a separate partition for Ubuntu manually, and you should select it while installing Ubuntu.