UBUNTU 10.04 lucid lynx
Ubuntu is an operating system built by a worldwide team of expert developers. It contains all the applications you need: a web browser, office suite, media apps, instant messaging and much more.
Ubuntu is an open-source alternative to Windows and Office.
* Ubuntu will always be free of charge, along with its regular enterprise releases and security updates
* Ubuntu comes with full commercial support from Canonical and hundreds of companies from across the world
* Ubuntu provides the best translations and accessibility features that the free software community has to offer
* Ubuntu core applications are all free and open source. We want you to use free and open source software, improve it and pass it on.
you can get it from here-
http://www.ubuntu.com/getubuntu/downloadubuntu 10.04
KUBUNTU 10.04
Kubuntu is an official derivative of the Ubuntu operating system using the KDE graphical environment instead of GNOME. It is part of the Ubuntu project and uses the same underlying system. It is possible to run both the KDE desktop (kubuntu-desktop) as well as the Gnome desktop (ubuntu-desktop) interchangeably on the same machine. Every package in Kubuntu shares the same repositories as Ubuntu.It is released regularly on the same schedule as Ubuntu
u can get it from here-
http://www.kubuntu.org/getkubuntu/downloadkubuntu 10.04