I'm on a Debian distro, it's been a long time that I edited Openbox menu.xml, so I forgotten that I had to use obmenu or whatever, I opened it in a normal text editor, edited something in the right-click menu. Then saved then restarted Openbox without reconfiguring it.
And now I can still login, after that all I see is a black screen with the mouse cursor. I tried opening the terminal using the Super key + T keyboard combination, but I can't see anything at all, no terminal, no web browser, just a cursor and a black screen.
Note, I can't boot to a live CD, due to a nomodeset issue. If nomodeset is on, my PC won't boot correctly, so I always set it to off, but when booting from a live CD, you can't set it to off.