IIS 5.0 Se reinicia solo, dando siempre 4 errores en el event view

Hola:
El entorno de trabajo que tengo montado es W2K, IIS 5.0 y (RSA ACE/Agent
5.2) que es un sistema de epass.
El problema que tenemos es que el servidor se reinicia solo con cierta carga
de trabajo (no sabemos exactamente las razones). Se reincia muchas veces solo
y si la carga de trabajo es constante, al final acaba callendose del todo.
A continuación pongo la descripcion de los 4 errores segun aparecen en el
event viewer.
1) Event Id: 7031
The IIS Admin Service service terminated unexpectedly. It has done this 8
time(s). The following corrective action will be taken in 1 milliseconds:
Run the configured recovery program.
2) Event Id: 7031
The FTP Publishing Service service terminated unexpectedly. It has done
this 66 time(s). The following corrective action will be taken in 0
milliseconds: No action.
3) Event Id: 7031
The Simple Mail Transport Protocol (SMTP) service terminated unexpectedly.
It has done this 66 time(s). The following corrective action will be taken
in 0 milliseconds: No action.
4) Event Id: 7031
The World Wide Web Publishing Service service terminated unexpectedly. It
has done this 66 time(s). The following corrective action will be taken in 0
milliseconds: No action.


A continuación siempre apare el siguiente mensaje de información:
1)Event ID: 2
IIS stop command received from user NT AUTHORITY\SYSTEM. The logged data is
the status code.
For additional information specific to this message please visit the
Microsoft Online Support site located at:
http://www.microsoft.com/contentredirect.asp.
2)Event ID:1
IIS start command received from user NT AUTHORITY\SYSTEM. The logged data is
the status code.
For additional information specific to this message please visit the
Microsoft Online Support site located at:
http://www.microsoft.com/contentredirect.asp.

Como veis es simplemente que se paran todos los servicios y se reinician,
pero no se las causas y ya lo he investigado todo.
Me podeis hechar un cable?.
Muchas gracias.