I've only installed an (xen) kernel-image (126.96.36.199) with apt-get. This changed the whole menue.list, created the initrd and ... demolished Grub. Now its not possible anymore to boot even not grub bootscreen can be seen. The file: stage1 and stage2 were missing in /boot/grub and if copied them back: cp /usr/lib/grub/i386-pc/stage1 /boot/grub But still grub will not show its bootmenue. Already grub was new installed by using grub-install - but no bootscreen. What to do?