A technician receives an urgent alert that a critical file server at a remote branch office has gone offline and is unreachable over the network. The server is accessible via out-of-band IPMI, which indicates that chassis power is present, but the power LED on the server is blinking amber instead of steady green. The IPMI system event log reports "System board voltage regulator failure" as the last critical event before the failure. Attempts to use the remote KVM show no video output, and Wake-on-LAN commands have no effect. The branch office has no on-site IT personnel; the only staff are general office workers with minimal technical training. The earliest a field technician can travel to the site is 48 hours. The main office has an identically configured spare server and a backup image of the file server's system disk. The branch office staff can follow simple plug-and-play instructions if provided. Which of the following is the BEST immediate course of action to restore the file services with minimal downtime?