Ubuntu 14.04 crashed and I don't know how to get it back. I'm stuck on GNU GRUB version
2.02~beta2-9ubuntu1.2. I've tried going to Advanced Options and choosing a recovery mode, but to no avail. What should I do?
You can use Ubuntu Installation Cd then once you boot it go through option
try Ubuntu... this will takes you to a live session.
Once you are in you can try to update your GRUB and restart. If this doesn't help boot again to liveCD and make a backup of your data then try to figure what crashes your system. If you can't get reasons you can just reinstall.
To install grub from live cd
Boot from a Live CD.
Hit Alt+Ctrl+T to open terminal and run following commands:
sudo mount /dev/sdaX /mnt
replace sdaX with your Ubuntu partition (mostly sda1)
Install the GRUB2 boot loader:
sudo grub-install --root-directory=/mnt /dev/sda
Rermark that installing grub to harddisk itself not the Ubuntu partition
Then Unmount the Ubuntu partition
sudo umount /dev/sdaX
Now restart and test it.