How to let RHEL v3 run 64-bit mode Only

From: Ross (Ross_at_nospam.com)
Date: 04/25/05 

Date: Sun, 24 Apr 2005 22:41:03 -0400

Hi there,
I have an AMD Opteron machine running RHEL v3 Update 2 which supports both
64-bit mode and 32-bit mode.
The question is: How can I force the system to run 64-bit mode only?

Thanks in advance,
Ross