Install (K)ubuntu Breezy Step 1: The system itself

Since I like to have alternatives, I first installed Ubuntu 5.10 Breezy Badger and got KDE later.
If ever I have problems with KDE, I can login on Gnome and reinstall KDE.

So first, go to http://www.ubuntu.com/download/ and choose a mirror nearby. Download the .iso - file which suits best for your computer and burn it to CD (choose: burn image) - voila your install CD.

Restart your PC (of course after having made a backup) and follow the instructions.
The only thing which can create problems is the partitioning. If you want to have a dual boot with windows, you nedd to partition your hard drive manually. I won't explain this because other people have done that already and better than I could here
Anyway I recommend not to set dual boot because I had a lot of problems with it.
If you want to set up only ubuntu you may choose the automatical partitioning (which will erase your entire harddisk including every operating system you used before!).

But don't be scared: most of the installation is self-explanatory

Of course you can also download kubuntu directly from here - if you do this, you can skip Step2 of this Blog. But keep in mind that in that case you'll only have kde.