[Centos] CentOS 3.1 kernel crashes

Greetings everyone,

I've got a problem with my fileserver running CentOS 3.1.  The kernel 
seems to crash about once a day (inevitably when I'm not present), 
forcing me to reboot.  This behavior started after I applied the new 
kernel patch (2.4.21-15.0.3.EL.c0).

I've left it on 2.4.21-15.0.2 for a little bit to see if it will crash 
tonight/tomorrow.  As this may be a hardware problem, I'm reluctant to 
put it into bugzilla until I can pin it on something.

The server has an A-Bit KR7A motherboard with an Athlon XP 1700+, 1.5 GB 
of RAM, 4 120 GB ATA-100 hard drives mirrored in two sets (hence I only 
have 240 GB available), a Cirrus Logic GD 5430 video card, and an Intel 
EtherExpress Pro 100.

There is nothing useful in /var/log/messages and the only reason I know 
when it crashes is due to my fetchmail log.

Has anyone else seen anything like this?  Did I patch too soon?

Any suggestions on where I might look for info on why it's crashing? 
The screen's blank and the keyboard lights are flashing.

Thanks in advance,

Shawn M. Jones