Thanks for your replies.
Swap file is same as I'm using on Mandrake 9.l ok
(trying to decide which to use to replace Man 8.1)
I couldnt get the knoppix disk to get me back to the installed knoppix so I re-installed it, then backed up /etc and /home with my settings.
Knoppix is the easiest distro to install I've had yet.
Perhaps the system wasn't stalled as I thought since after the backup (with tar) the mouse and keyboard slowed badly, and shutdown took a very long time and I just waited it out. On restart speed is ok.
My machine is 330mb ram with 300 speed and I'm using usb2 - swap is 130mb - I have about 740mb free on the hard disk - perhaps this machine doesnt have power for knoppix?