I found this - hope it's of some use, Jere, and welcome to PC Pals!
Auto Reboot On System Crash[/u]
By default, when the Windows XP operating system crashes an automatic reboot of the system occurs. While this behavior can be convenient, the downside is the error message accompanying the crash is not visible. Often times this information can be a great help in troubleshooting the source of the crash. This behavior can be modified as follows:
Open System Properties via Start > Control Panel > Performance and Maintenance > System
[ System Properties may also be opened using the WinKey+Pause key combination ]
Select the Advanced tab and then click Settings in the Startup and Recovery section
In System Failure section, clear the checkbox next to Automatically Restart
Click OK and OK to exit
It should be noted that when you disable the Automatic Restart option you may be presented with the screen below.
This is most likely to occur if the page file has been relocated to a different drive in order to improve virtual memory performance.
By disabling Auto Reboot, you may be able to see the error message, and thus discover the cause of the crash.