A technician needs to replace a computer's hard drive. Which of the following should the technician do FIRST?

Removing network connections is not required before internal hardware replacement and is unrelated to electrical safety.

Removing RAM is an action performed during repair, not a preparatory safety step, and is certainly not done before powering down.

Self-grounding on the case is an ESD precaution that comes after power is disconnected, as grounding on a live case can still pose electrical risk.

Disconnecting power to the PC ensures there is no live current flowing through any components, which is the primary safety requirement before opening a case or touching internal hardware. Residual current or accidental power-on can destroy components or injure the technician. All other preparatory steps follow after power is safely removed.