Restore GRUB2 MBR from SLAX Linux

When you log in into slax type:

mount -t proc proc /mnt/hda3/proc
mount -o bind /dev /mnt/hda3/dev
chroot /mnt/hda3 /bin/bash
grub

then

find /boot/grub/stage2
root (hd0,2)
setup (hd0)
quit

Then exit and reboot.