A user's workstation experiences unexplained intermittent shutdowns throughout the work day. The user has not reported any recent changes to the system or environment. As a technician, what is the most likely hardware component to begin troubleshooting this problem based on the symptom described?
Central Processing Unit (CPU)
Random Access Memory (RAM)
System's solid-state drive (SSD)
Power Supply Unit (PSU)
Graphics Processing Unit (GPU)
Motherboard