[CentOS] What is the System Event Log?

My Dell PowerEdge T105 running Centos-5.2 has started crashing fairly often (3 times in the last 2 hours). The message on the screen tells me to look at the System Event Log. Is this just /var/log/messages ?

I didn't see anything helpful there. As far as I could see, the last messages before the crash were about samba, which is running on the machine. Has anyone had such problems with Samba? I've stopped the smb service to see if this improves matters.

I'm running a standard updated system. I looked at smartctl but this did not suggest that there was anything wrong with the 2 SATA disks.

Incidentally, wouldn't it be a good idea for /var/log/messages* to start a new file when booting?