Hi nickp,

No one to help ? Here is something to do that should help find where the problem is.

Please confirm you are using Knoppix 6.4.4. with the LXDE desktop.

Reboot and when the desktop comes open an LXTerminal (if in doubt, click on the third button in on the bar at the bottom of the screen).

In the terminal, type in top. This shows a list of the processes running on your machine. It refreshes every second or so. Processes near the top are using most CPU. When the system is idle, Xorg, compiz, init and and top are likely to be up there.

Type ^C to stop top. Copy and paste the lines from the top of the terminal down to kthreadd into a file so you can post them later. Start top again. Now start up video and wait for everything to go slow. Type ^C to stop top again and copy / paste the top few lines etc.

Post what you get and we'll have a look see what that tells us.