That's the KDE desktop in SuSe, so if you install SuSe as your distro the most you would probably have to do is set the background image to make it look exactly like that.

Live CD :
A CD that allows you to boot directly into Linux, rather than having to install it first. Most commonly used to try out a distribution prior to doing an install. (there are other uses; I'm sure you can think of some, but the try-before-you-install is what we're interested in here).

Most Linux distributors provide a Live CD version, and it can be a good way to experiment. However, my personal experience has been they run very slowly, so they don't really give an accurate feel for the software.


Desktop Environment :
Short answer: Install Suse; pick the default options; you'll get the KDE suite of desktop software. I wouldn't worry too much about which desktop software to use; you can always experiment later on; for now, your first task is to just getting it up and running.

Longer answer:
Take KDE for example: KDE is a (large) collection of software that put together forms the bulk of what you'll see in your every-day Linux usage. It's the graphical interface: the icons, the windows, the buttons, etc, and also a collection of useful programs (web browser, config program, media player, etc). Put it all together, and you have a desktop environment.
Gnome is another example. It does pretty much the same job as KDE, so all the above applies to it as well. There's several others available as well, but KDE and Gnome are the ones you're most likely to use.

The thing with Linux is that you can mix and match things, so you have the freedom to choose KDE or Gnome, or whatever else. But if you're installing Suse, you're most likely to end up using KDE. And to be honest, that's probably the best option for you (especially if it's what your friend uses).

Well to be simple a desktop environment is what you click on. The icons, the windows and so on. On windows, the desktop environment is windows and you don't have the choice. It is a background with icons you can click on and a start menu with menus. In the linux world, there are tons of different things you can choose from. You would like the start menu to open at right click on the back ground and you don't need a task bar? use fluxbox. You like the start menu at the bottom? Use KDE... If you like MacOSX style desktop, install MacOS X desktop like.
You do what you want. This is confusing at start because linux doesn't choose for you, but that is what linux is.
Desktop environment is not the distribution, you can have nearly any desktop environment with nearly any distribution. Most distribution choose one for you though, but you can change it anyway.

Now the best way to go is to install Suze as you already have the CD and as some other people pointed out. You will quickly learn about all this. You have some things to learn if you want to use linux to its full power. It will take some times, but once you know it you will wonder how on earth you would do without several functionalities not available in windows.

Or, just download this : http://www.knoppix.net/get.php
It is a well known live CD (knoppix). Burn it and just boot your computer with the CD just burnt in the CD drive. It will start a full linux system with KDE. It will be a bit slow but you won't notice. I chose that for you but there are literally thousands of different live CDs. Play around and see if you like it. You may learn some stuff about linux from it as well.

If you install rar or unrar then ARK and File Roller can handle rar files.

Will a LiveCD run on my computer at the moment (i have windows, no linux drives at all)

Yes it will. A live cd just needs enough ram and a cdrom/dvd drive.

I really have to start looking at how many pages are in a thread. Then I wouldn't have to edit an answer that was allready posted.

Heh I think we've all done that a time or two..