As described in detail in https://bugzilla.altlinux.org/show_bug.cgi?id=23723, in School Lite 5.0.1: in the installer, testing X makes the screen black, and the computer doesn't respond any more to any key combinations. So, in order to complete the installation, one shouldn't test X. Also after the installation, X doesn't start.
(In reply to comment #0) > Also, after the installation, X doesn't start. https://bugzilla.altlinux.org/show_bug.cgi?id=23725
Also, similarly to to what happens in an installed system -- https://bugzilla.altlinux.org/show_bug.cgi?id=23723 , switching to a text console in the installer makes probably the graphical installer crash after a while (or perhaps it is switching back to the console with the graphical installer that makes the screen black), and then blocks the computer, so that it doesn't respond to any key combinations.