I just rebooted an Ubuntu Server 10.04. After choosing boot options in the grub menu, though, it just displays a black screen with the blinking white underscore in the upper-left corner.
The machine has had (hardware) trouble with networking before, but the problem remains after 10 minutes, so I don't think it's the problem now. Booting into recovery mode or using earlier kernels yields the same problem. This also happens if I boot from another hard-drive.
I haven't yet tried to boot from CD as the machine lacks a CD reader.
How should I diagnose the problem?
Update: My boot options are:
recordfail insmod ext2 set root='(hd0,1)' search --no-floppy --fs-uuid --set 567[redacted] linux /boot/vmlinuz-2.6.32-29-generic root=UUID=567[redacted] ro quiet splash initrd /boot/initrd.img-2.6.32-29-generic
Update: Also, I cannot access the virtual terminals (ctrl+alt+Fn).