It is easy to fix, first you need a boot cd of opensuse and call ‘yast2 bootloader’ and it will remake /boot/grub/menu.lst, of course you need to tell it you want it look at the advance options, if you lose the grub read the post To install a 3rd OS? - openSUSE Forums because i have post there how to install a grub already if you have problems in the future with the grub.