My Ms Office not working so need to fix

My installation of Microsoft Excel suddenly refuses to open—every attempt ends in an immediate crash before any workbook appears. I need someone who can diagnose what is causing the failure to launch and guide me through, or remotely execute, a clean fix.

Scope of work
• Inspect possible causes such as recent Windows or Office updates, COM add-ins, template corruption, or damaged registry keys.
• Run or advise on safe-mode tests, Quick/Online Repair, and any targeted fixes (e.g., removing problematic add-ins, repairing office via Control Panel).
• Restore full, stable startup of Excel so I can open and edit files normally again.

I will grant remote-access (TeamViewer/AnyDesk) if required, and can perform steps myself under clear instruction if that is safer. Once Excel launches reliably, I consider the job complete.