Knoppix is typically run from the CD, which is read-only, so there'd be no way to install anything that isn't included with the base distribution.
You can install Knoppix onto a HDD, and if that's what you did, I'll suggest something you're bound to run into often in the Linux world. RTFM. There's bound to be information on what that password is in the Knoppix documentation if you look for it.
I've downloaded my Knoppix and placed on CD by image file. I've been able to go online, and create documents and so forth. But i cannot view videos. I've gone to the site to download the Linux MPEG viewer so i can see www.youtube.com and so forth. When i try and launch the downloaded program for installation.. It's telling me that i need a password (maybe to make changes, or something) why would it ask for a password. And what is the password i'm looking for.

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