Can anyone point me in the right direction.
I have a 13.2 64 bit kde install. With the packman multimedia rpm’s and an updated kernel 3.17.1-5.1.Was just running knonueror, amarok, dolphin and chrome and the system just locked up. I had to do a forced p/c shut down.
The log files are normally in /var/log, have a look in the messages file (as superuser), around the time before the restart, assuming you rebooted since
Unfortunately, just noticed there is no messages log file there any more thanks to systemd. There is a “README” file in its place, explaining how to get the “journal” replacement or alternative ways for syslog. 
Install “rsyslog” and you will get messages back.
Is this possibly a freeze related to your graphics display? Those occasionally happen on my laptop with Intel graphics. It isn’t logged, because the system is frozen at the time.
Many thanks.
I have installed rsyslog. Hopefully my system crash was a one-off but I wanted to be in a position to see what happened if it happens again.