Windows 7 not booting after installing Ubunutu

win_7_not_loading_after_ubuntu_install

I have fed up for one day after i was unable to load my windows 7 after installing Ubuntu 12.04 LTS.

I'm gonna share some things i learned while recovering my system from this problem.

Mistakes Done by me:

1. Formatted the small partition(some thing around 200 MB) created automatically wile installing Windows 7.
2. Did not allocate swap space while installing Ubuntu.

Outcome of the Mistakes:

1. Dual boot mode is not working.
2. By default Ubuntu is booting.
3. There is no boot menu at all.

My Approach to Solve the problem:

1. I thought that while installing ubuntu, Windows 7 booting link was missed.So I thought to re-establish the link to boot Windows 7.

2. I googled and did the following procedure to bring a boot menu.

3. I installed boot-repair and done recommented repair:
3.a sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update
3.b sudo apt-get install boot-repair

4. I installed Grub Customizer
4.a sudo add-apt-repository ppa:danielrichter2007/grub-customizer
4.b sudo apt-get update
4.c sudo apt-get install grub-customizer

5. Now boot menu came. but windows 7 is not there.

6. So I thought to add windows 7 to boot menu by
6.a cd /etc/grub.d
6.b sudo gedit 40_custom
6.c Add the following lines to the end of the file:

menuentry "Windows 7" --class windows --class os {
     insmod part_msdos
     insmod ntfs
     set root='(hd0,msdos1)'
     search --no-floppy --fs-uuid --set=root UUID-GOES-HERE
     drivemap -s (hd0) ${root}
     chainloader +1
  }

hd0 means 1st hard disk.
msdos1 means first partition of the disk(sda1 means msdos1,sda2 means msdos2,..etc). we can find out where boot of windows 7 is installed using the command "sudo fdisk -l"
UUID can be obtained by the following command "sudo blkid"

7. sudo update-grub2

8. sudo reboot

9. Now Windows 7 is showing in boot menu.

10. When I clicked its showing error "bootmgr is missing.. press ctrl+alt+del to restart".

11. Now I installed windows 7 usb boot and did the following steps:

11.a In Command prompt type:
11.a.i. bootrec /RebuildBcd
11.a.ii. bootrec /FixMbr
11.a.iii. bootrec /Fixboot
11.b. Give option automatically fix boot issues.

12. restart and load windows 7. now its working.