Slack 10.2, KDE 3.5, Mozilla
I had been having a few lockups but only on one user (I have 2 different user setups for different tasks).
I was browsing and all of a sudden xine started up, I tried to kill it but it would not work, I did ps -e and there were like 20 instances of xine so i tried to kill X ctrl-alt-bkspc, and that didnt work. 2 seconds later my system shutdown on its own.
I disconnected the ether cable and reboot. In the user I had the problems all the icons were gone and everything was really screwed up. I logged into the other user that I dont use to access the internet and it was fine.
My question is does this sound like some kind of intrusion or just X crashing?

check 'more /var/log/messages' for security/system log, 'more /var/log/Xorg.log' (or whatever the filename, i forget) for X server log, and 'dmesg | less' for other system events.

I dont have any /system directory or system.log file anywhere.

i didnt say you did.. open konsole and execute the commands i wrote in single quotes.. if you get permission error, try the commands as root