remove old linux kernel in ubuntu

dpkg -l linux-* | awk '/^ii/{ print $2}' | grep -v -e `uname -r | cut -f1,2 -d"-"` | grep -e [0-9] | xargs sudo apt-get -y remove

Ubuntu installation

Ubuntu provides a very user-friendly interface. I will recommend it for desktops and laptops. However, since the installation media is a CD-ROM, the preinstalled softwares are limited. Here are procedures for additional softwares:

1) add a Medibuntu repository, including many commerical softwares which ubuntu cannot include in their own repositories, such as acroread, skype, mplayer. Check the method here. For instance, for 8.0.4(hardy),

• Ubuntu 8.04 "Hardy Heron":

  sudo wget http://www.medibuntu.org/sources.list.d/hardy.list -O /etc/apt/sources.list.d/medibuntu.list
  

Then, add the GPG Key:

sudo apt-get update && sudo apt-get install medibuntu-keyring && sudo apt-get update

then you can use "sudo apt-get install acroread" to install the adobe acrobat reader, as well as its mozilla plugin.
2) install LaTeX
sudo apt-get install tetex-base tetex-bin tetex-extra

3) install emacs, gnuplot, grace ....,

Some problems:
1) for nvidia graphical cards, the system will prompt you to install an enhanced driver nvidia-glx. However, there's a bug which messes up with your LCD monitor refresh rate. A temporary solution is to edit /etc/X11/xorg.conf, in Device section, add
Option "DynamicTwinView" "false"