I tried to triple boot Windows xp, Fedora 14 and Ubuntu 10.04. I first installed Windows xp, then fedora followed by Ubuntu. The problem is that i don't get option to boot Ubuntu while Xp boots fine. It seems Ubuntu was unable to replace Fedora's grub with its own at MBR. Looking at their grub conf file, Fedora and Ubuntu identifies same harddisk as two different devices and i do have another 80 GB harddisk which doesn't have any OS. Below is the details on my partitions and partial information from grub files of both OS. Device Boot Start End Blocks Id System /dev/sda1 * 63 40965749 20482843+ 7 HPFS/NTFS /dev/sda2 102414436 312576704 105081134+ f W95 Ext'd (LBA) /dev/sda3 40965750 102414374 30724312+ 83 Linux - /Home (for fedora) /dev/sda5 102414438 204812684 51199123+ 7 HPFS/NTFS /dev/sda6 204812748 253634219 24410736 83 Linux -- ubuntu /dev/sda7 253634283 302455754 24410736 83 Linux -- fedora /dev/sda8 302455818 312576704 5060443+ 82 Linux swap / Solaris grub.cfg from ubuntu ### BEGIN /etc/grub.d/10_linux ### menuentry 'Ubuntu, with Linux 2.6.32-21-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod ext2 set root='(hd1,7)' search --no-floppy --fs-uuid --set cd55e078-a2c1-4d8a-9e87-ae838b6f4a05 linux /boot/vmlinuz-2.6.32-21-generic root=UUID=cd55e078-a2c1-4d8a-9e87-ae838b6f4a05 ro quiet splash initrd /boot/initrd.img-2.6.32-21-generic } menuentry 'Ubuntu, with Linux 2.6.32-21-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod ext2 set root='(hd1,7)' search --no-floppy --fs-uuid --set cd55e078-a2c1-4d8a-9e87-ae838b6f4a05 echo 'Loading Linux 2.6.32-21-generic ...' linux /boot/vmlinuz-2.6.32-21-generic root=UUID=cd55e078-a2c1-4d8a-9e87-ae838b6f4a05 ro single echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-2.6.32-21-generic } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod ext2 set root='(hd1,7)' search --no-floppy --fs-uuid --set cd55e078-a2c1-4d8a-9e87-ae838b6f4a05 linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod ext2 set root='(hd1,7)' search --no-floppy --fs-uuid --set cd55e078-a2c1-4d8a-9e87-ae838b6f4a05 linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Microsoft Windows XP Professional (on /dev/sdb1)" { insmod ntfs set root='(hd1,1)' search --no-floppy --fs-uuid --set cad48cc6d48cb5eb drivemap -s (hd0) ${root} chainloader +1 } menuentry "Fedora (2.6.35.14-96.fc14.i686) (on /dev/sdb6)" { insmod ext2 set root='(hd1,6)' search --no-floppy --fs-uuid --set 6aee34cf-f77a-489a-9361-85d07194b84b linux /boot/vmlinuz-2.6.35.14-96.fc14.i686 ro root=UUID=6aee34cf-f77a-489a-9361-85d07194b84b rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us rhgb quiet initrd /boot/initramfs-2.6.35.14-96.fc14.i686.img } menuentry "Fedora (2.6.35.6-45.fc14.i686) (on /dev/sdb6)" { insmod ext2 set root='(hd1,6)' search --no-floppy --fs-uuid --set 6aee34cf-f77a-489a-9361-85d07194b84b linux /boot/vmlinuz-2.6.35.6-45.fc14.i686 ro root=UUID=6aee34cf-f77a-489a-9361-85d07194b84b rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us rhgb quiet initrd /boot/initramfs-2.6.35.6-45.fc14.i686.img } ### END /etc/grub.d/30_os-prober ### grub.conf from fedora default=0 timeout=5 splashimage=(hd0,5)/boot/grub/splash.xpm.gz hiddenmenu title Fedora (2.6.35.14-96.fc14.i686) root (hd0,5) kernel /boot/vmlinuz-2.6.35.14-96.fc14.i686 ro root=UUID=6aee34cf-f77a-489a-9361-85d07194b84b rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us rhgb quiet initrd /boot/initramfs-2.6.35.14-96.fc14.i686.img title Fedora (2.6.35.6-45.fc14.i686) root (hd0,5) kernel /boot/vmlinuz-2.6.35.6-45.fc14.i686 ro root=UUID=6aee34cf-f77a-489a-9361-85d07194b84b rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us rhgb quiet initrd /boot/initramfs-2.6.35.6-45.fc14.i686.img title Other rootnoverify (hd0,0) chainloader +1