Hi all,

I just did a fresh install of Windows 7 and then Ubuntu 12.04 (because of this problem). My problem is that grub did not install in the MBR (Windows starts automatically). I'm able to boot in Ubuntu using the Ultimate boot CD and "Super Grub 2", which easily finds the grub config file on /dev/sda6.

So I tried the usual

Code:
sudo update-grub 
sudo grub-install /dev/sda
but still nothing.

I saw several threads about the same subject but they were quite complex cases, whereas I don't see anything special in my config?
and it's not the first time I install an Ubuntu with this kind of config. am I missing something stupid?

Also don't know if that matters but I did the installation using a USB drive (I checked that my hard drive was /dev/sda, anyway that should have worked the second time at least).

Here is the bootinfoscript output:
Code:
                  Boot Info Script 0.61      [1 April 2012]


============================= Boot Info Summary: ===============================

 => Windows is installed in the MBR of /dev/sda.

sda1: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows Vista/7: NTFS
    Boot sector info:  No errors found in the Boot Parameter Block.
    Operating System:  Windows 7
    Boot files:        /bootmgr /Boot/BCD /Windows/System32/winload.exe

sda2: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows Vista/7: NTFS
    Boot sector info:  No errors found in the Boot Parameter Block.
    Operating System:  
    Boot files:        

sda3: __________________________________________________________________________

    File system:       Extended Partition
    Boot sector type:  -
    Boot sector info: 

sda5: __________________________________________________________________________

    File system:       ext4
    Boot sector type:  -
    Boot sector info: 
    Operating System:  
    Boot files:        

sda6: __________________________________________________________________________

    File system:       ext4
    Boot sector type:  -
    Boot sector info: 
    Operating System:  Ubuntu 12.04 LTS
    Boot files:        /boot/grub/grub.cfg /etc/fstab

sda7: __________________________________________________________________________

    File system:       ext4
    Boot sector type:  -
    Boot sector info: 
    Operating System:  
    Boot files:        

sda8: __________________________________________________________________________

    File system:       swap
    Boot sector type:  -
    Boot sector info: 

============================ Drive/Partition Info: =============================

Drive: sda _____________________________________________________________________

Disk /dev/sda: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition  Boot  Start Sector    End Sector  # of Sectors  Id System

/dev/sda1    *          2,048   122,882,047   122,880,000   7 NTFS / exFAT / HPFS
/dev/sda2         122,882,048   368,642,047   245,760,000   7 NTFS / exFAT / HPFS
/dev/sda3         368,642,048   625,141,759   256,499,712   5 Extended
/dev/sda5         368,644,096   471,044,095   102,400,000  83 Linux
/dev/sda6         471,046,144   544,774,143    73,728,000  83 Linux
/dev/sda7         544,776,192   618,504,191    73,728,000  83 Linux
/dev/sda8         618,506,240   625,141,759     6,635,520  82 Linux swap / Solaris


"blkid" output: ________________________________________________________________

Device           UUID                                   TYPE       LABEL

/dev/sda1        781A64FB3C86B129                       ntfs       
/dev/sda2        7D9A7E49385BFDF9                       ntfs       shared
/dev/sda5        a05e448e-1a28-4939-8fa7-e4fb216f0da7   ext4       data
/dev/sda6        59b6ce17-6b15-4bbc-a70a-5cf6857f09a7   ext4       
/dev/sda7        3634f488-e56a-4df9-866f-509d4744d644   ext4       linux2
/dev/sda8        8aa76b03-2f9a-4bb2-a42a-ade389eaefd4   swap       

================================ Mount points: =================================

Device           Mount_Point              Type       Options

/dev/sda1        /media/windows           fuseblk    (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096)
/dev/sda2        /media/shared            fuseblk    (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096)
/dev/sda5        /media/data              ext4       (rw)
/dev/sda6        /                        ext4       (rw,errors=remount-ro)
/dev/sda7        /media/linux2            ext4       (rw)


=========================== sda6/boot/grub/grub.cfg: ===========================

--------------------------------------------------------------------------------
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  set have_grubenv=true
  load_env
fi
set default="0"
if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}

function recordfail {
  set recordfail=1
  if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi
}

function load_video {
  insmod efi_gop
  insmod efi_uga
  insmod video_bochs
  insmod video_cirrus
}

insmod part_msdos
insmod ext2
set root='(hd0,msdos6)'
search --no-floppy --fs-uuid --set=root 59b6ce17-6b15-4bbc-a70a-5cf6857f09a7
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  insmod part_msdos
  insmod ext2
  set root='(hd0,msdos6)'
  search --no-floppy --fs-uuid --set=root 59b6ce17-6b15-4bbc-a70a-5cf6857f09a7
  set locale_dir=($root)/boot/grub/locale
  set lang=en_IE
  insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ]; then
  set timeout=-1
else
  set timeout=10
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
if background_color 44,0,30; then
  clear
fi
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
function gfxmode {
	set gfxpayload="${1}"
	if [ "${1}" = "keep" ]; then
		set vt_handoff=vt.handoff=7
	else
		set vt_handoff=
	fi
}
if [ "${recordfail}" != 1 ]; then
  if [ -e ${prefix}/gfxblacklist.txt ]; then
    if hwmatch ${prefix}/gfxblacklist.txt 3; then
      if [ ${match} = 0 ]; then
        set linux_gfx_mode=keep
      else
        set linux_gfx_mode=text
      fi
    else
      set linux_gfx_mode=text
    fi
  else
    set linux_gfx_mode=keep
  fi
else
  set linux_gfx_mode=text
fi
export linux_gfx_mode
if [ "${linux_gfx_mode}" != "text" ]; then load_video; fi
menuentry 'Ubuntu, with Linux 3.2.0-23-generic' --class ubuntu --class gnu-linux --class gnu --class os {
	recordfail
	gfxmode $linux_gfx_mode
	insmod gzio
	insmod part_msdos
	insmod ext2
	set root='(hd0,msdos6)'
	search --no-floppy --fs-uuid --set=root 59b6ce17-6b15-4bbc-a70a-5cf6857f09a7
	linux	/boot/vmlinuz-3.2.0-23-generic root=UUID=59b6ce17-6b15-4bbc-a70a-5cf6857f09a7 ro   quiet splash $vt_handoff
	initrd	/boot/initrd.img-3.2.0-23-generic
}
menuentry 'Ubuntu, with Linux 3.2.0-23-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
	recordfail
	insmod gzio
	insmod part_msdos
	insmod ext2
	set root='(hd0,msdos6)'
	search --no-floppy --fs-uuid --set=root 59b6ce17-6b15-4bbc-a70a-5cf6857f09a7
	echo	'Loading Linux 3.2.0-23-generic ...'
	linux	/boot/vmlinuz-3.2.0-23-generic root=UUID=59b6ce17-6b15-4bbc-a70a-5cf6857f09a7 ro recovery nomodeset 
	echo	'Loading initial ramdisk ...'
	initrd	/boot/initrd.img-3.2.0-23-generic
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry "Memory test (memtest86+)" {
	insmod part_msdos
	insmod ext2
	set root='(hd0,msdos6)'
	search --no-floppy --fs-uuid --set=root 59b6ce17-6b15-4bbc-a70a-5cf6857f09a7
	linux16	/boot/memtest86+.bin
}
menuentry "Memory test (memtest86+, serial console 115200)" {
	insmod part_msdos
	insmod ext2
	set root='(hd0,msdos6)'
	search --no-floppy --fs-uuid --set=root 59b6ce17-6b15-4bbc-a70a-5cf6857f09a7
	linux16	/boot/memtest86+.bin console=ttyS0,115200n8
}
### END /etc/grub.d/20_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
menuentry "Windows 7 (loader) (on /dev/sda1)" --class windows --class os {
	insmod part_msdos
	insmod ntfs
	set root='(hd0,msdos1)'
	search --no-floppy --fs-uuid --set=root 781A64FB3C86B129
	chainloader +1
}
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
--------------------------------------------------------------------------------

=============================== sda6/etc/fstab: ================================

--------------------------------------------------------------------------------
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sda6 during installation
UUID=59b6ce17-6b15-4bbc-a70a-5cf6857f09a7 /               ext4    errors=remount-ro 0       1
# /media/data was on /dev/sda5 during installation
UUID=a05e448e-1a28-4939-8fa7-e4fb216f0da7 /media/data     ext4    defaults        0       2
# /media/linux2 was on /dev/sda7 during installation
UUID=3634f488-e56a-4df9-866f-509d4744d644 /media/linux2   ext4    defaults        0       2
# /media/shared was on /dev/sda2 during installation
UUID=7D9A7E49385BFDF9 /media/shared   ntfs    defaults,umask=007,gid=46 0       0
# /media/windows was on /dev/sda1 during installation
UUID=781A64FB3C86B129 /media/windows  ntfs    defaults,umask=007,gid=46 0       0
# swap was on /dev/sda8 during installation
UUID=8aa76b03-2f9a-4bb2-a42a-ade389eaefd4 none            swap    sw              0       0
--------------------------------------------------------------------------------

=================== sda6: Location of files loaded by Grub: ====================

           GiB - GB             File                                 Fragment(s)

 242.835166931 = 260.742275072  boot/grub/grub.cfg                             1
 226.026367188 = 242.693963776  boot/initrd.img-3.2.0-23-generic               2
 226.745834351 = 243.466485760  boot/vmlinuz-3.2.0-23-generic                  1
 226.026367188 = 242.693963776  initrd.img                                     2
 226.745834351 = 243.466485760  vmlinuz                                        1
Thanks for your help!