Ubuntu (virtual machine same) replace the kernel?

1: View the currently installed kernel
Dpkg-l|grep Linux-image

2: View the version of the kernel that can be updated:
sudo apt-cache search Linux-image

3: Install the new kernel
sudo apt-get install linux-image-3.13.0-74-generic linux-image-extra-3.13.0-74-generic

4: Uninstall the not kernel
sudo apt-get purge linux-image-3.13.0-xx-generic linux-image-extra-3.13.0-xx-generic

5: Update Grub Boot
sudo update-grub

Reboot the system to view.

Note the memory allocation situation ...

Ubuntu (virtual machine same) replace the kernel?