I have a Panasonic Toughbook CF-19 MK3 that I recently installed Xubuntu 12.04 LTS on. That install went smoothly and works fine. Was looking for more customization, so decided to try KDE desktop. Used apt-get to install KDE 4.8.5. Everything was working fine after install until I rebooted; once I did that I had login issues (couldn't login, but was using KDE login manager - switched it back to XFCE login manager and that was solved).
Once I was able to login to a KDE session, I got this issue: as soon as I tough ANY key on the keyboard OR the touchpad, the screen goes black for a while. Eventually it comes back, but goes black upon key press/touchpad use. I tried editing the compositing line in the .kde/share/config/kwinrc file to Enabled=false, then rebooted, but that doesn't seem to do anything.
I've spent about 2 hours searching for answers on the internet, but I have not been able to find a solution. Anyone have any ideas? I want to try KDE, but this is frustrating! I'm relatively new to Linux also, and I'm trying to use Linux exclusively now (no Windows!)