kubuntu's KDE desktop not booting properly

[sparkwave]

My kubuntu laptop boots to a black screen with a command line cursor (the cursor isn't blinking and I can't enter anything), and with KDE Dark Breeze mouse cursor that I can control, for some reason.
Ctrl + F2 doesn't do anything at all.
Rebooting doesn't solve the problem.
Booting to a previous Linux kernel has the same effect.
The kubuntu logo shows properly on startup.
The recovery mode seems to work properly, and allows me to enter commands.
A very simple solution would be to reinstall it, but is there anything more that I can do about this?
Thanks in advance.

[maglin2]

Possibly worth trying
ctrl + alt + f1

or f2 etc up to f7?

- though having now spotted your comment that you've got a controllable mouse cursor I doubt if that will achieve much.