I have broken my boot sequence on my XP/Vista/Ubuntu box. I wish to restore the system back to the way that Ubuntu 9.04 (last installed OS) had it setup. I want to do only the mbr and /boot on the ubuntu partition and leave the rest of the system alone. How can I do this using the ubuntu 9.04 live CD?
Follow the Ubuntu Community instructions on restoring or recovering from a boot-loader problem. Essentially, you'll have to chroot into your hard drive environment using your live CD and use grub-install to reinstall GRUB. There are multiple ways to do this as suggested by the document - choose your pick.
Use Ubuntu's Live CD. Restart your machine, and boot into the disk.
Choose the try ubuntu option ,make sure that your pc is connected to the network. If the connection was lost, right click on the Network Connection icon, and choose edit. Add a network by putting in ips, dns, etc then hit apply
Open the terminal by combination of the keys Control + alt + t. Type
sudo apt-install grub then afterwards enter
update-grub. Restart your machine, things should be fixed!