JSI Tip 10068. You are unable to print to a network printer after you install security update 896423 on a computer that is running Windows 2000 with Service Pack 4?

Microsoft Knowledge Base Article 908506 contains the following description:

Fixes a problem where you can no longer print to a Lexmark, Dell, or IBM printer after you install security update 896423 and Update Rollup 1 for Windows 2000 SP4.