I have a system with ubuntu-14.04.2-desktop-amd64 installed. It has stopped booting up after updating. As I power on it, screen glows for 1 sec and it shuts down. I have tried to open GRUB boot loader by pressing SHIFT key while booting but nothing happened, screen just glows for a second and goes off. This happens sometimes, most of time as I power on the wifi symbol gets on and laptop shuts down.The screen doesn't glow in this at all. I downloaded the Ubuntu from net and installed with the help of bootable USB on laptop.It's been 2 days and I have a lot of data in the laptop.
Any Solutions/Suggestions ? Thanks In advance.