Ok,

I take it you run Windows, right? Tell me one thing: When you install a program in Windows, it just doesn't install the program, does it? It installs drivers, libraries, and support files, for the program, right?

So, in essence, any program, that is installed, needs to place other files, more likely, into the system files area. Linux/Knoppix is no different, it needs to add files to the areas of the system. Using the Live CD allows you to, as in the case of Shareware, "Try before you buy." But in the case of Knoppix, you don't have a buy issue.

You can't update the system files if you are running Knoppix just from the CD. You can get some configuration changes by using the Setup a Persistant Knoppix Configuration, and using the Save Knoppix Configuration - but to install programs, may require more than that, possibly going to a Hard Drive Install. As many programs, even in the Windows World, require more than just adding a program, one program updates libraries and support files, that in turn, require other updates to support another program. I.e. Internet Explorer updates some files that other programs use as well, and they in turn need to be updated - as in the case of Windows. Knoppix keeps track of these "dependencies" for you, and when you add a new program, that changes these dependencies, Linux knows what else needs to be updated.

For this reason, running from the CD allows you "some" abilities, but not to an extent of adding external programs. (mostly)

Cuddles