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bwayakethy's avatar
bwayakethy
Iron Contributor
Aug 19, 2026

High CPU usage when no applications are running on Computer

My computer shows extremely high CPU usage even when no applications are running, which causes the system to slow down significantly. Despite closing all programs and background processes, the CPU usage remains abnormally high, making it difficult to use the computer normally and raising concerns about possible malware, system errors, or hardware issues that need to be diagnosed and resolved.

2 Replies

  • Jason_M's avatar
    Jason_M
    Iron Contributor
    Aug 19, 2026

    Having no applications open does not mean the CPU is idle. Windows Update, Defender scans, third-party services, faulty drivers and malware can all run in the background. The first step is to identify the exact process using the CPU rather than ending processes at random.

    1. Press Ctrl + Shift + Esc, select More details, and open the Processes tab.
    2. Select the CPU column to sort from highest to lowest. Leave Task Manager open for two or three minutes and note the process that stays at the top.
    3. If it is Windows Modules Installer Worker, Windows Update or Antimalware Service Executable, connect the charger, allow it to finish for about 30 minutes, check for Windows updates, and restart the computer. Do not forcibly end these system processes.
    4. If a third-party program, updater or manufacturer utility is responsible, update or uninstall it. Also open the Startup tab in Task Manager and disable unnecessary startup applications.
    5. Run a malware check through Windows Security > Virus & threat protection > Scan options. Run a Full scan, followed by Microsoft Defender Offline scan if nothing suspicious is found but the usage remains high.
    6. To check Windows system files, open Command Prompt as administrator and run these commands one at a time:  
      DISM /Online /Cleanup-Image /RestoreHealth sfc /scannow
    7. If System interrupts is using significant CPU, disconnect nonessential USB devices and update the laptop or motherboard manufacturer’s chipset, storage, network and audio drivers. Persistent System interrupts usage usually points to a driver or hardware problem.
    8. If the cause is still unclear, perform a clean boot: press Win + R, enter msconfig, open Services, select Hide all Microsoft services, and then select Disable all. Disable startup apps in Task Manager and restart. Re-enable the disabled items gradually to find the cause.

    One important detail: a high value for System Idle Process is normal because it represents unused CPU capacity. The process name and its CPU percentage are the most useful information for determining the next step.

  • KapilArya's avatar
    KapilArya
    MVP
    Aug 19, 2026

    Please refer these suggestions:

    Try to fix corruption with system files:

    1. Search for 'windows powershell' using Windows Search.

     

    1. From results, choose Windows PowerShell and select Run as administrator.

     

    1. Then type/paste following and press Enter key:

     

    Repair-WindowsImage -Online -RestoreHealth

     

    1. Let the command complete, restart your system then.

     

    Additionally, scan your system using built-in Windows Security, or AV program you're using. 

    If issue still persists, you can suggestions in this fix:

    https://www.kapilarya.com/fix-windows-10-high-cpu-usage-problem

    Let us know if this helps!

    Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.