Why would anyone want to do that?

Well I now have a reason, My laptop running Ubuntu 14.04 suddenly started crashing. On 15th March it crashed more than 10 times.

I tried to figure out what had happened to my normally functioning machine all of a sudden. I had installed regular update early in the morning that day. Turns out that, I had updated my kernel to 3.13.0-83. That was only software installed that day, and if my laptop was crashing for software reasons there was only one possible culprit!

Thus I rebooted my machine, and selected older kernel version from my grub menu to start ubuntu. It worked normally.

Now I was sure my new linux kernel was giving all the problems, I had to uninstall it. Here is how I did that:

Step 1: List all the kernels installed in the system

$ dpkg --list | grep linux-image

ii  linux-image-3.13.0-24-generic                         3.13.0-24.47                                        amd64        Linux kernel image for version 3.13.0 on 64 bit x86 SMP
ii  linux-image-3.13.0-83-generic                         3.13.0-83.127                                       amd64        Linux kernel image for version 3.13.0 on 64 bit x86 SMP
rc  linux-image-4.4.0-13-generic                          4.4.0-13.29~14.04.1                                 amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP
ii  linux-image-extra-3.13.0-24-generic                   3.13.0-24.47                                        amd64        Linux kernel extra modules for version 3.13.0 on 64 bit x86 SMP
ii  linux-image-extra-3.13.0-83-generic                   3.13.0-83.127                                       amd64        Linux kernel extra modules for version 3.13.0 on 64 bit x86 SMP
ii  linux-image-generic                                   3.13.0.83.89                                        amd64        Generic Linux kernel image

Step 2: Remove kernel you don't want anymore

Okay, before moving further! If you are trying to do something like this please make sure you don't remove all your kernels. Leave atleast one: probably the one that works for you. In my case I wanted to keep 3.13.0-24.

I removed buggy kernel version 3.13.0-83.

$ sudo apt-get purge linux-image-3.13.0-83-generic

Here is the output I could see in my screen when I removed my kernel:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  kde-l10n-engb libechonest2.1 libqtweetlib1.0
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  linux-generic* linux-image-3.13.0-83-generic*
  linux-image-extra-3.13.0-83-generic* linux-image-generic*
0 upgraded, 0 newly installed, 4 to remove and 0 not upgraded.
After this operation, 195 MB disk space will be freed.
Do you want to continue? [Y/n] Y
(Reading database ... 207828 files and directories currently installed.)
Removing linux-generic (3.13.0.83.89) ...
Removing linux-image-generic (3.13.0.83.89) ...
Removing linux-image-extra-3.13.0-83-generic (3.13.0-83.127) ...
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 3.13.0-83-generic /boot/vmlinuz-3.13.0-83-generic
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 3.13.0-83-generic /boot/vmlinuz-3.13.0-83-generic
update-initramfs: Generating /boot/initrd.img-3.13.0-83-generic
run-parts: executing /etc/kernel/postinst.d/pm-utils 3.13.0-83-generic /boot/vmlinuz-3.13.0-83-generic
run-parts: executing /etc/kernel/postinst.d/update-notifier 3.13.0-83-generic /boot/vmlinuz-3.13.0-83-generic
run-parts: executing /etc/kernel/postinst.d/zz-update-grub 3.13.0-83-generic /boot/vmlinuz-3.13.0-83-generic
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.13.0-83-generic
Found initrd image: /boot/initrd.img-3.13.0-83-generic
Found linux image: /boot/vmlinuz-3.13.0-24-generic
Found initrd image: /boot/initrd.img-3.13.0-24-generic
Found memtest86+ image: /boot/memtest86+.elf
Found memtest86+ image: /boot/memtest86+.bin
done
Purging configuration files for linux-image-extra-3.13.0-83-generic (3.13.0-83.127) ...
Removing linux-image-3.13.0-83-generic (3.13.0-83.127) ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.13.0-83-generic /boot/vmlinuz-3.13.0-83-generic
update-initramfs: Deleting /boot/initrd.img-3.13.0-83-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.13.0-83-generic /boot/vmlinuz-3.13.0-83-generic
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.13.0-24-generic
Found initrd image: /boot/initrd.img-3.13.0-24-generic
Found memtest86+ image: /boot/memtest86+.elf
Found memtest86+ image: /boot/memtest86+.bin
done
The link /vmlinuz is a damaged link
Removing symbolic link vmlinuz 
 you may need to re-run your boot loader[grub]
The link /initrd.img is a damaged link
Removing symbolic link initrd.img 
 you may need to re-run your boot loader[grub]
Purging configuration files for linux-image-3.13.0-83-generic (3.13.0-83.127) ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.13.0-83-generic /boot/vmlinuz-3.13.0-83-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.13.0-83-generic /boot/vmlinuz-3.13.0-83-generic

Step 3: restart your system

sudo reboot