I have Windows 8.1 and Ubuntu 13.10 dual booting on my Acer laptop. A week after i install Ubuntu 13.10, my laptop crashed. I choose to repair windows first because i run many important programs on windows, but unfortunately, the grub loader is missing and i can't open my Linux although it isn't missing actually. If you have the same problem, this maybe some solutions:

Getting Boot-Repair

1st option : get a CD including Boot-Repair

The easiest way to use Boot-Repair is to burn one of the following disks and boot on it.

• Boot-Repair-Disk is a CD starting Boot-Repair automatically. (English only, 32&64 bits compatible, based on Debian-live so WiFi and RAID drivers are old).
• Boot-Repair is also included in Ubuntu-Secure-Remix (multi-languages, OK for WiFi and RAID, 32 or 64 bits, based on Ubuntu 12.04 LTS, run Boot-Repair from the Dash, the 64 bits version is UEFI-compatible)

Remark : you can also install the ISO on a live-USB (eg via LiliUSB or MultiSystem).

2nd option : install Boot-Repair in Ubuntu

- boot your computer on a Ubuntu live-CD or live-USB.

- choose "Try Ubuntu"

- connect internet

- open a new terminal (CTRL + T) , then type:

sudo add-apt-repository ppa:yannubuntu/boot-repair

-press Enter

sudo apt-get update

- Press Enter.

- Then type:

sudo apt-get install -y boot-repair && boot-repair

- Press Enter

Using Boot-Repair

Recommended repair

• launch Boot-Repair from either :
  • the Dash (the Ubuntu logo at the top-left of the screen)
  • or System->Administration->Boot-Repair menu (Ubuntu 10.04 only)
  • or by typing 'boot-repair' in a terminal
• Then click the "Recommended repair" button. When repair is finished, note the URL (paste.ubuntu.com/XXXXX) that appeared on a paper, then reboot and check if you recovered access to your OSs.
• If the repair did not succeed, indicate the URL to people who help you by email or forum.