Investigate Windows Server and WordPress Issue

Need to professional investigate an issue with my dedicated Windows server, which is affecting my WordPress site (and another site). The site is not reachable at all now.
But the server is accessible via the vKVM Rescue System, as detailed here: https://docs.hetzner.com/robot/dedicated-server/virtualization/vkvm#starting-the-rescue-system.
When testing the WordPress admin panel at http://localhost/<sitename>/wp-admin it returns an HTTP Error 404, The requested resource is not found.

Key Requirements:
- Diagnose and resolve the server issue preventing the WordPress site from functioning.
- Access the server through the vKVM Rescue System.
- Investigate and fix the server issue .
- Possible (if a reinstall required) Download a MySQL database backup, and some other files.

Ideal Skills and Experience:
- Expertise in Windows server administration and troubleshooting.
- Experience with WordPress site management and error resolution.
- Familiarity with using vKVM Rescue System for server access.
- Proficiency in handling MySQL databases and backups.

Please help restore the functionality of my WordPress site and ensure the server is running smoothly.