I just used the screensaver preferences link in the Debian section of KMenu. When it asked to activate I said no, and clicked to disable in the preferences.

I use Debian testing (Squeeze) and I guess I don't do too many complicated things as I enjoy KDE 4. I also used KDE for all my time in Linux and really didn't switch over to KDE 4 until a couple of months after it appeared in Squeeze, only checking out the progress using Live CD until that point. I kept Lenny on my main system until that point. I seem to have bypassed most of the major bugs by waiting.

The update-alternatives --config commands were useful to me in order to prevent lxde getting involved, which is the default in Knoppix. Everything I've encountered so far using KDE tools has been working fine with the exception of Powerdevil. That appears to be ignoring my setting the performance edits to not turn off my monitor. And I get a warning on login that there appears to be no user assigned to apply powerdevils preferences. But I have no trouble simply moving the mouse to turn my monitor back on without a password prompt.

For my screen I installed the nvidia drivers the Debian way using module-assistant and the sid debian nvidia packages. I let nvidia-xconfig revamp the xorg.conf and nvidia auto-select just appeared to use what I had been using the knoppix cheat code screen=1024x768 and depth=24 while the nv driver had been automatically been used prior to my installing nvidia. Once the nvidia drivers were installed I had no need to use the cheat codes, which would do nothing to the resolution as once nvidia-xconfig made its own xorg.conf the knoppix bootup then always states that it was not modifying my customized xorg.conf. KDE just automatically uses what nvidia setup.

I suppose I could have kept the Knoppix X setup by just issuing the cheatcode xmodule=nviidia (as I had used successfully in previous Knoppix 6 setups), but that would have required that I keep using the screen and depth cheat codes. This way (nvidia-xconfig) I allow nvidia-settings to do its thing without the massive Knoppix xorg.conf inserting all those depreciated commands. Xorg really doesn't need all that stuff anymore.

After commenting out the stable repos, changing default-release to testing in /etc/apt/apt.conf.d/00KNOPPIX, and adding debian-multimedia.org's squeeze main and non-free in menu.list, I've even been doing aptitude safe-upgrade daily and Knoppix is purring along with updated Squeeze packages. I only installed mplayer, libdvdcss2, acroread, and w32codecs from debian-multimedia and allowed the safe-upgrades to their other packages. Seems to get my codecs running fine. I fixed Quicktime trailers by purging the mozilla-mplayer and totem-mozilla and adding gecko-mediaplayer-plugin.

All that and I still have 1.9 GB free in my FAT32 limited 3888 MB sized knoppix-data file on the 8GB USB stick. Since I'm using the DVD, it already has just about any program I use installed so I think things will go fine.