Resolve Node.js Dependency Errors

My Node.js site (running on Windows with Node 8) used to start fine, but now it crashes immediately, complaining that the “express” module is missing. I’ve already run `npm install` and it finishes without any errors, yet the server still refuses to boot.

I need someone to trace the root cause—whether it’s a corrupted node_modules folder, a mismatched package-lock, an outdated script, or something else—then patch the project so it launches cleanly again.

Deliverables:
• A working start-up of the site on my machine, with clear reproduction steps.
• A concise write-up of what was wrong and the fixes applied (so I can maintain it going forward).