1.) http://www.supergrubdisk.org/
2.)3.) Wenn du dir nichtmal sicher bist, welchen Bootmanager du hast, bleib bei Win.1. Boot from the CD/USB flash drive from which you installed Ubuntu
2. Open terminal (It is there under Accessories)
3. type in sudo fdisk -l
4. then type sudo mount /dev/sdAB /mnt , where A is your drive and B is your linux partition. In my case, I typed in sudo mount /dev/sda7 /mnt
5. install GRUB again by typing this sudo grub-install --root-directory=/mnt /dev/sdA , where A is your drive. In my case, I typed sda
6. Now type sudo umount /mnt
4.) Pimp mal deine Google Skills, ich hab sofort was gefunden. Oder lügst du etwa?