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Knoppix comes with KDE as default desktop environment and it's very similar in appearance to Windows (a severe design problem if you ask me

). There are tons and tons of window managers and desktop environments that are more or less similar to Windows - most fall in the "less" category.
Notepad, eh? Pick your poison. kedit and kate are KDE apps, I use gvim (which cannot be compared to the lowly Notepad program since it's really a full blown development environment), there is gedit (from the Gnome desktop) and tons more.
Killing processes in Linux is not quite as easy as in Windows. But on the other hand - in Linux processes you want killed really die if you want them to!

Open up an xshell. I think you will find a shell icon on your desktop or in the panel at the bottom of your screen. Here's where the real magic happens.

Type
killall processname to kill all instances of a process. You can find out the name of the running processes by typing
ps -e (and it's going to be a whole lot of processes). If a process is particularily stubborn you can type
kill -9 process_id to forcefully kill it in an instance. process_id is the number before the name of the process in the ps -e listing. You can also use
top to see what process use a lot of CPU and RAM.
There are a few graphical tools for this kind of stuff but I don't use them. You might have something called
ktop on Knoppix though. It's the KDE equivalent of the Task Manager in Windows.
Håkan