What is the most likely cause of a computer spontaneously shutting down after a few minutes?

A computer that spontaneously shuts down after a brief period of operation is often experiencing overheating issues, particularly related to the CPU. When the CPU overheats, it can trigger automatic thermal protection mechanisms designed to prevent damage to the processor and other components. This process typically results in the computer shutting down abruptly to cool down.

Several factors can lead to an overheated CPU. Dust accumulation can obstruct airflow, causing inefficient cooling. A malfunctioning fan or inadequate thermal paste between the CPU and its heat sink can also lead to overheating. In environments with high ambient temperatures or insufficient ventilation, the risk of overheating is further increased.

While other issues like malware, power supply failure, or memory problems can also cause system issues, their manifestations differ significantly. For instance, malware may cause slowdowns or unusual behaviors rather than immediate shutdowns, power supply failures often lead to unexpected reboots rather than a quick shutdown, and memory problems typically result in system instability or error messages rather than outright shutdowns. Thus, overheating of the CPU is the most likely cause of the observed behavior of the computer shutting down after just a few minutes of use.