Does anybody know where can i install knoppix....???
To your hard-drive?
Seriously, best to use a new and separate hard drive if you can, if you are concerned about partitioning. Open a root console and execute the 'knoppix-installer' script. See http://www.knoppix.net
for more documentation.
If the above is gibberish to you, try Mepis
instead. It's based on Knoppix, but has a very newbie-friendly graphical installer program.