Mandrake 9 server went down. How do I figure out what caused it?
 

My linux server (Mandrake 9.1) has been in operation for about 10 months with no issues. However, Sunday it was unresponsive. No SAMBA, No APACHE, I couldn't even get the monitor to respond to see what happened.

So, I rebooted. It came up without a problem and has been working just as usual. No known missing files, programs etc....

Is there a log file somewhere that would track what might have gone wrong?

you could browse /var/log/ for new files, i.e. messages.2, messages.3, etc. whatever the latest number would be the last file. if there's nothing new, you could look at application specific log files. for that you'd need to read up on the apps in ? and where specifically the log files for those apps are stored on your sys, and distro. hope that helps.
good luck.