Zorin OS Lite does not install, what am I doing wrong?

I've been trying to install Zorin for 2 hours and I don't know why it fails?

I burned the ISO onto a DVD and inserted it into the laptop.
From there the whole thing also starts wonderfully, that Live System appears and I can select the installation folder and then the part leads me through the system through the installation. After I have arrived at the window with the user data and password and then click on Next, the window closes and the mouse pointer changes into a "circle shop symbol".

Nothing happens, the system is not installed, nothing, where is the error here?

Try deactivating the UEFI secureboot and repeat the Zorin OS installation. Many Linux distributions require that secureboot be deactivated.

I don't think he did, the computer. (AMD Athlon XP, all 2003)

In a comment you name "AMD Athlon XP" as the processor. This is a 32-bit processor!
If your Linux ISO is designed for a 64-bit processor, then that won't work.

Some distributions no longer have a 32-bit ISO. Is Zorin one of them?

I know from Manjaro that they still offer 32-bit systems.

See my answer