2003 unexpected shutdown

Hello support,

We have a Windows Server 2003 x64 system that at seemingly random intevals

(anywhere from 5 to 10 hours apart) reaches 100% CPU usage and locks up. The

system is running in a virtual environment (Citrix XenServer) with another

Windows Server 2003 guest that have no problem at the time of the incident.

There are no logs in the virtual host to suggest a problem, aside from a

restart taking place which must be manually initiated, the Windows Server

does not restart on its own.

The system was configured with 4x vCPUs and 2gb RAM. The host has 4 CPUs

(Intel Xeon 3Ghz) and 4Gb RAM.

The only entry in the Windows Event Log that suggests a problem is the one

event to say "unexpected server shutdown", suggesting something hardware

related - though nothing reported in the host log, and the second virtual

guest is unaffected.

We have since dropped the server down to 2 vCPUs. While the server remained

running over the weekend, we have just had a repeat failure.

We've not had a problem with this host in the past, and is isolated to this

one virtual guest. Can anyone suggest a way to increase the logging to

determine what may be causing the crash?

Many thanks,

Steve