When I start the computer it seems ubuntu is loading normally, but a few seconds later I get black screen with this message:
BusyBox v1.21.1 (Ubuntu 1:1.21.0 - 1ubuntu1) built-in shel (ash)
Enter 'help' for a list of built in commands
(initramfs)_
From there I can only 'reboot'. I typed 'help' and i got a list of commands i dont know and tried some of them like exit