Why won't my Linux Mint boot after I manually installed a new kernel?
apt-get install linux-image-newerone
dpkg -l|grep linux-image|grep extra
ii linux-image-extra-3.16.0-38-generic 3.16.0-38.52~14.04.1 amd64 Linux kernel extra modules for version 3.16.0 on 64 bit x86 SMP
If you get a result you need the extra kernel because during install Linux detected some drivers to make your system run were in the "extra" kernel package (I stronlgy disagree with this separation as it is easy to break your system now!).
Here's how to fix it.
1.) For the exact kernel version eg. 3.19.0-80.88~14.04.1 (you can remove anything after the third dot .)
2.) Set the variable like above and run the following command:
sudo apt-get install linux-image-headers-$kernelversion linux-image-extra-$kernelversion