Which of the following should be checked FIRST when troubleshooting a computer that intermittently shuts down after heavy usage?

Printer paper levels are completely unrelated to a computer shutting down and would never cause an unexpected system shutdown.

Insufficient RAM causes performance degradation, application crashes, or excessive paging but does not directly cause the system to power off intermittently.

Optical drive device drivers affect disc read and write operations and would not cause the entire computer to shut down unexpectedly.

Modern CPUs have built-in thermal protection that forces an immediate shutdown when temperature thresholds are exceeded to prevent hardware damage. A failing CPU fan cannot dissipate heat during sustained heavy workloads, causing the CPU to overheat and trigger this protective shutdown, making it the first component to check.