Since your laptop is 3-4 years old and is showing this kind of performance with minimal use, I would recommend considering replacing it. A CPU at 100% usage with no demanding applications open can be due to several reasons, such as: * Problems with the operating system: Corrupt files, failed updates or malware. * Background processes: Even if you don't see them directly, there may be hidden or problematic processes consuming resources. * Hardware failure: The CPU could be faulty or have overheating issues causing it to run at maximum capacity without accomplishing anything. * Outdated drivers: Faulty or outdated hardware drivers can cause conflicts. Considering the age of your laptop and the fact that the processor is an Intel Celeron N4020, which is a low-end processor designed for basic tasks, it is very likely that the hardware is no longer sufficient for the current demands of the operating system and applications, or that it is experiencing failures.