Hello Dan Me,
Since safe mode is also failing, the issue is likely deeper than a simple add-in conflict. These are the most realistic options at this point:
- Open Run (
Win + R), typewinword /aand hit Enter — this launches Word bypassing both add-ins and registry customizations, which is a step beyond standard safe mode. - Right-click the Word shortcut → Properties → Compatibility tab → set compatibility mode to Windows XP (Service Pack 3).
- If neither works, a clean reinstall of Office 2003 with SP3 applied immediately after is worth attempting.
That said, Windows 11 has had significant changes to legacy shell components and Office 2003 is well beyond its supported lifespan. You can consider upgrading to a modern version (Office 2024, Microsoft 365) as the reliable long-term path forward.