Don't worry chrisblack! Have some faith in humanity.
Knoppix wont touch your hard drive or your windows installation.
However, it might touch your computing soul (provided you have your boot priorities straight in the CMOS) giving you operating system freedom like you have never felt before!

So, download the .iso image, burn it with your favorite windows cd-burning software, and boot it ( set boot priority 1-floppy, 2-cdrom, 3-hard drive), push enter, sit back and be amazed with internet access, free open office software, and utilities galore.

Moustache