A technician is building a high-powered workstation.

When a newly built workstation shows no response at all—no fans spinning, no indicator LEDs, and no POST activity—this indicates that the system is not receiving the signal to power on. Since the technician has already verified that all primary power connectors are fully seated (including the 24-pin ATX motherboard connector and the 4-pin or 8-pin CPU power connector), the most likely cause is that the case header pins are not connected to the motherboard.

According to CompTIA Core 1 (220-1201) hardware installation and troubleshooting concepts, the power button on the computer case connects to the motherboard via the front-panel (system panel) header, specifically the PWR_SW pins. If this connector is missing, improperly placed, or connected to the wrong pins, pressing the power button will do nothing because the motherboard never receives the power-on signal.

Incorrectly seated RAM typically allows the system to power on but prevents successful POST, often resulting in beep codes or error lights. An underpowered PSU usually causes instability, random shutdowns, or failure under load rather than complete inactivity. A faulty CPU fan connector generally triggers a BIOS warning or shutdown after power-on, not total failure to start.

This scenario directly matches CompTIA’s emphasis on checking front-panel connections as a primary step when a system does not power on at all.