Fix Node.js Site Startup Issue

My website, built with Node.js, is not starting on my computer using 'npm start'. I need someone to fix this problem and teach me how to manage the site.

Requirements:
- Diagnose and fix the startup issue
- Provide a tutorial on site management
- Patience and clarity in explanation

Ideal Skills:
- Proficiency in Node.js
- Experience with Windows OS
- Strong teaching and communication skills