I have installed ubuntu allongside windows7 64bit on seperate hdd, on reboot sysem would only see and boot to windows os, after using boot repair via live disk grub reinstall and grub update, on reboot the system now shows ubuntu grub and boots to ubuntu the option to boot to windows partiton is not visable, tried using windows repair disk to repair boot files no joy, here is some info update grub threw up. generating grub. cfg... found linux image:boot/vmlinuz-3.5.0-17-generic found initrd image: /boot/initrd.img 3.5.0-17-generic found memtest86+ image: /boot/memtest86+bin error: ddf1:wrong# os devices in raid set "ddf1_ssdraid" [1/2] on /dev/sdd done. hope this helps if any more info is needed let me know