this i am especially confused on

But if you like a 100% linux system. you will have to make changes on your hard disk. You can use qtparted to resize and create new partitions. It is very easy to do it.
i don't mind a little change on my hard disk as long as it's a matter of a simple partition, leaving windows intact, and nothing more.. which is why i am looking at a dual boot loader, but that's seeming like a bit more than i can chew at the moment..

is a dual boot loader necessary if you have windows and knoppix both installed to the hard drive? or does it just make switching between the two easier? how easy is it to switch with/without a dual boot loader, or is it even possible without one?

thanks for reading