first step:
Still need to enter the Ubuntu interface, but does not need to be installed (if they are directly installed, the previous file in Ubuntu which can be all gone, so as a last resort, do not do this).
How to enter Ubuntu interface it believed should be installed over Ubuntu you will, here I can only say one way:
Ready Ubuntu U disk to start (the best and the same as the original system) with a floppy disk through UltraISO.
Step two:
Try entering the Ubuntu interface, and connect the network (because the network will need follow-up).
third step:
Open a terminal, the terminal shortcut key is Ctrl + Alt + T, enter:
sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update
Then always follow the prompts.
the fourth step:
Re-enter the terminal:
sudo apt-get install -y boot-repair && boot-repair
Wait a minute, will appear the following interface:
there will be this, click Recommended repair, restart a few minutes on the line.
the fifth step:
If some people do not accidentally clicked Create a BootInfo summary, then your boot screen will come out a lot of things you have not seen before.
In that case, you can enter a name to make:cd /boot/grub
Then enter sudo gedit grub.cfg, open grub.cfg file, found by searching windows, then put the following will be deleted and the same as the original.
### BEGIN /etc/grub.d/25_custom ###
menuentry "efi/EFI/Boot/bootx64.efi" {
search --fs-uuid --no-floppy --set=root d000ed6a-5303-40aa-a517-af50e807c0e9
chainloader (${root})/efi/EFI/Boot/bootx64.efi
}
menuentry "efi/EFI/ubuntu/MokManager.efi" {
search --fs-uuid --no-floppy --set=root d000ed6a-5303-40aa-a517-af50e807c0e9
chainloader (${root})/efi/EFI/ubuntu/MokManager.efi
}
menuentry "Windows UEFI recovery bootmgfw.efi" {
search --fs-uuid --no-floppy --set=root A603-846C
chainloader (${root})/EFI/Microsoft/Boot/bootmgfw.efi
}
menuentry "Windows Boot UEFI recovery" {
search --fs-uuid --no-floppy --set=root A603-846C
chainloader (${root})/EFI/Boot/bkpbootx64.efi
}
menuentry "EFI/ubuntu/MokManager.efi sda2" {
search --fs-uuid --no-floppy --set=root A603-846C
chainloader (${root})/EFI/ubuntu/MokManager.efi
}
menuentry "Windows UEFI recovery LrsBootmgr.efi" {
search --fs-uuid --no-floppy --set=root 7607-5674
chainloader (${root})/efi/Microsoft/Boot/LrsBootmgr.efi
}
menuentry "Windows Boot UEFI recovery bkpbootx64.efi" {
search --fs-uuid --no-floppy --set=root 7607-5674
chainloader (${root})/efi/Boot/bkpbootx64.efi
}
Reference Hirofumi
Ubuntu 14.04 repair guide (Boot Repair) (a double system repair)