Ну тогда # grub-mkconfig -o /boot/grub/grub.cfg
И ещё раз перезапустите компьютер.
После этого точно должно работать!
# grub-mkconfig -o /boot/grub/grub.cfg
Generating grub.cfg ...
Found theme: /boot/grub/themes/slinux/theme.txt
Found background image: grub.jpg
Found linux image: /boot/vmlinuz-std-def
skipping symlink: /boot/vmlinuz-std-def
Found linux image: /boot/vmlinuz
Found initrd image: /boot/initrd.img
Found linux image: /boot/vmlinuz-3.0.40-std-def-alt0.M60P.1
Found initrd image: /boot/initrd-3.0.40-std-def-alt0.M60P.1.img
Found linux image: /boot/vmlinuz-un-def
skipping symlink: /boot/vmlinuz-un-def
Found linux image: /boot/vmlinuz-3.4.9-un-def-alt0.M60P.1
Found initrd image: /boot/initrd-3.4.9-un-def-alt0.M60P.1.img
Found linux image: /boot/vmlinuz-3.0.13-std-def-alt0.M60P.1
Found initrd image: /boot/initrd-3.0.13-std-def-alt0.M60P.1.img
No volume groups found
Found memtest image: /boot/memtest-4.20.bin
done
И делаю рэбут