Nothing that Windows has is necessary for Knoppix to run. You could absolutely wipe your HD and still run Knoppix from CD, or install from CD. There are various options.

I really hate to see you do anything drastic until you have lived with linux for a while. It's a remarkable OS, but it's still in development. Enough of us have had the panic of having the Windows OS wiped out by accident, and then we're left with an unfamiliar OS. I can't imagine that you want to do that to yourself on purpose just yet.

Maybe I'm misunderstanding and maybe you are dealing with an extra machine that you don't have to rely upon working. You need to disabuse yourself of the notion that a hd install is "easier". Very experienced linux folks have spent weeks here trying to resolve small problems which arise in a hd installation. There is no tech support to call. There are very few wizards. Compatability problems generally involve editing files. The nature of some of your questions leads me to have a concern that you may not be prepared for that. Maybe you're used to the idea that things are easier in Windows with a HD install - not necessarily so for linux.

I would really do poor man's if I were you. If you're ready for HD install, great. Be sure to back up all your data first, though!