My computer fans are running at full speed and the laptop is hot even though nothing is open. Task Manager shows CPU at 80-100%. What is causing this?
High CPU with nothing visibly open means something is running in the background. Open Task Manager (Ctrl+Shift+Esc), sort by CPU column. Common culprits: 1) Windows Update (TiWorker.exe or Windows Modules Installer Worker). Let it finish and restart. 2) Antivirus performing a full scan. Schedule scans for off-hours. 3) Malware, especially crypto miners designed to use maximum CPU. Run Windows Defender full scan then Malwarebytes free. 4) A stuck process or service. Right-click the high-CPU process and End Task. 5) Dust buildup clogging vents and heatsink. Use compressed air to blow out vents. If the laptop is over 3 years old and never cleaned internally, this is very likely contributing. Check the Processes tab to identify the exact culprit before trying random fixes.
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