Final answer:
After cleaning dust from a fan in a server with overheating issues, inadequate thermal paste is the most likely explanation for continued overheating. Faulty power supply, failed hard drive, or failed CPU could also cause overheating, but the symptoms suggest issues with thermal paste are more probable.
Step-by-step explanation:
If a rack-mounted server continues to overheat after cleaning dust from a fan, this suggests that a different component may be the cause of the overheating. One explanation could be inadequate thermal paste between the CPU and its heat sink or cooler. Thermal paste is crucial for conducting heat away from the CPU to the cooler effectively. If the thermal paste is old, improperly applied, or has dried out, it can lead to poor heat conduction and result in overheating. Other potential reasons such as a faulty power supply, a failed hard drive, or a failed CPU can also lead to overheating, but considering the symptoms, the thermal paste is a more likely candidate. A faulty power supply would typically cause system instability or not power on at all, whereas a failed hard drive or CPU would generally cause system crashes or not boot at all, although they might also overheat. It is important to also ensure that all fans are operating correctly, the air flow is not obstructed, and the server is not placed in a poorly ventilated area.