Manually Fixing High CPU Usage

Posted by Bob, Slimware

Although fixing problems with automated tools such as SlimCleaner Plus or DriverUpdate is our recommended route, we have compiled step-by-step instructions to fixing the most common issues below. WARNING: these instructions are intended to be followed precisely.

The very first thing you should do is to REBOOT YOUR COMPUTER!!! It is easy to forget this very important diagnostic step when troubleshooting computer problems.

To begin troubleshooting high CPU usage, start by making sure your computer is up-to-date, including Windows, hardware device drivers, anti-virus definitions and any other updates for 3rd party applications. Sometimes, updates will correct problems that result in high CPU usage. Remove unneccessary peripheral devices such as printers and webcams to eliminate further potential problems.

After making sure your computer is up-to-date, run a scan using your anti-virus software to ensure that your computer is free of infection. You may also use online anti-virus scanners as well for better scanning accuracy. If you do not have an anti-virus/malware scanner installed, we recommend you download a free antivirus program from our antivirus comparison page.

Troubleshoot Running Processes

The processor can only handle so much work at once. If the processor is at 100% and won't go lower, try closing some applications. If all of your applications are closed but the CPU usage is still at 100%, there may be too many processes running in the background.

First, eliminate the processes that start up with your computer. You can use Windows' System Configuration tool to do this...

  1. Click Start

  2. (Windows XP)

    Click Run 

    (Windows Vista/7)

    Type "Run" into the Search field and press Enter. The Run dialog will open in a new window.

  3. Type into the Run dialog: msconfig

  4.   Run Dialog
  5. Press Enter

  6. The Microsoft System Configuration utility will open in a new window.

      Mirosoft System Configuration Utility
  7. Click the Startup tab at the top of the new window.

  8. Disable the first startup item by un-checking the box next to it.

  9. Restart the computer

Remember to restart the computer after disabling each individual startup item. The point of this step is to eliminate the startup processes as a potential cause of the root problem. If disabling a startup item relieves the stress from the processor, you have found the problem. Keep disabling startups until there aren't any left. You may have to re-enable certain ones that are responsible for system processes. It is safe to ignore processes that are from Microsoft and any other programs that you are familiar with. If anything looks suspicious or unfamiliar, disable it. If disabling a process causes undesirable effects, you know you have disabled an important process. If disabling startup items does not fix the problem, proceed ahead for further troubleshooting.

The processor can only handle so much work at once. If the processor is at 100% and won't go lower, try closing some applications. If all of your applications are closed but the CPU usage is still at 100%, there may be too many processes running in the background. To troubleshoot running processes and services, you can use a free program like Process Explorer (DOWNLOAD).

Download process explorer and save it to the Desktop. Launch process explorer from the icon (right-click and choose "Run as administrator" if you are using Windows Vista/7). The interface will populate a list of the running processes on your computer. Hover the mouse over an individual item or right-click it and select Properties to see the services running behind a given process (if any). Svchost.exe will appear in multiple instances and may host one or more services at a time. This is normal. However, in some instances, a service hosted by an svchost process may be hosting a virus, causing a memory leak or may be stuck in an infinite loop, causing the processor to constantly run at max load. The purpose of Process Explorer is to eliminate processes one at a time to identify the one causing the problem.

Process Explorer

Notice the red-colored graph in the top navigation bar of Process Explorer. Click once on the red mini graph and a new window will open to display a full view of the CPU graph. Hover the mouse cursor over the highest points on the graph to reveal the process that is consuming the most resources. Make a note of the processes that are using the most resources and find them in the main process explorer interface. Right-click a suspect process and select Kill Process.

Remember to be careful when killing processes as there are many system services running in the background too. It's safe to ignore Microsoft processes and others that you are familiar with; but, if anything looks suspicious, kill it to see if it is causing the problem.

NOTE:If you kill a process that causes the Desktop, all of the icons and the taskbar, you have mistakenly killed Explorer.exe. This process should restore itself automatically; if it does not, press Ctrl + Alt + Del to bring up the Task Manager. To restore Windows Explorer...

  1. Click File
  2. Click Start Task (Run)
  3. Type into the dialog box: explorer.exe
  4. Click OK
  5. The Desktop should now be restored. If the Desktop does not appear after a few minutes, manually force shutdown of the computer by holding the power button down for 4-8 seconds.

    You should be able to determine the problem process running on your computer by eliminating them one at a time in this fashion, but if extensive troubleshooting has yielded no decrease in processor usage, it is still likely that the problem stems from corrupted system files, worm/trojan infection, hardware failure (i.g. memory failure, disk failure).

    Repair installation of Windows...

    To troubleshoot corruption of the operating system, you can perform a repair installation by following the steps outlined for your installed version of Windows.

    To attempt this fix, you will need the Windows installation/recovery CD/DVD that came with your computer. If you did not receive one or you have lost it, you may want to contact the manufacturer for one, purchase one on the Internet or else move on to the next section. A repair installation of Windows is different for each Windows operating system. In order to perform the repair installation correctly, follow the steps designated for your operating system...

    Windows XP:

    1. Insert the Windows XP CD/DVD into the disc drive.

    2. Boot the computer using the Windows XP CD/DVD.

      You may need to change the boot order in the system BIOS! To access the BIOS setup, you must press a particular key when your computer is booting up. The key differs per manufacturer but it is usually either Esc, F1-F12, Delete.

    3. When you see the "Welcome To Setup" screen, press ENTER

    5. Accept the License Agreement

      Windows will now search for existing installations of Windows.

    6. Select the XP installation you want to repair from the list.

    8. Press the R key to start the repair.

    9. The setup will copy the necessary files to the hard disk and reboot automatically.

      Do not press any keys during the setup. Windows may reboot several times.

    10. Follow the instructions provided by Windows to complete the initial setup but choose to "Activate Windows Later" when prompted.

    11. Once the setup is complete, it is critical that you download and install all updates from Microsoft.

    Windows Vista:

    1. Insert the Windows Vista/7 DVD into the disc drive.

    2. Press any key to boot from CD or DVD...

    4. The Setup will load and prompt you for the language, time and input method you wish to proceed in. Enter your preferences from the options provided and click Next once you are finished.

      Do not click Install Now!

    6. Click Repair your computer

      Windows will search for installations of Windows.

    7. Select the Windows Vista/7 installation you would like to repair.

    8. Click on the Load Drivers button

    9. Click the Next button

    10. Select the Startup Repair tool from the list that appears.


      If the Startup Repair initiates automatically, ignore this step.

      The Startup Repair process will take some time to finish. Your computer may reboot several times.

      If you are prompted to restore the computer using System Restore, click Cancel.

    11. Once finished, you will have the option to view the details of the repair. Simply click Finish to continue.

    12. Windows Vista may run through the initial setup phase. Simply follow the instructions but choose to "Activate Windows Later" when prompted.

    13. Once the setup is complete, it is critical that you download all updates from Microsoft.

    Windows 7:

    1. Log on to Windows 7 as an administrator.

    2. Disable any 3rd party firewall, antivirus or any other security software.

    3. Insert the Windows 7 CD/DVD into the disc drive.

    4. If the AutoPlay menu pops up, select the option "Run setup.exe"

      If AutoPlay does not appear, double-click Computer on the desktop, double-click on the disc drive icon, and run the setup.exe file within.

    5. If prompted by the User Account Control, select Yes

    6. Click on the Install Now button.

    7. Click the Go online to get the latest updates for installation option

      Windows will now check for any available installation updates.

    8. Accept the license agreement from Microsoft.

    9. Click the Upgrade option

      Windows will now begin the repair process.

      The computer will reboot several times during installation.

    10. Once the setup is finished, you will be asked for your Windows 7 product key.

    11. Uncheck the box next to Automatically activate Windows when I'm online

    12. Click the Use recommended settings option.

    13. Windows will guide you through the rest of the initial setup.

    14. Once Windows has loaded, it is critical that you download and install all updates from Microsoft.

    15. Do not forget to re-enable your anti-virus and firewall.

    After these extensive troubleshooting methods, the CPU usage should now be alleviated to some degree, but if it persistently runs at a constantly high speed, you should consider taking your computer to a repair store to get the hardware checked. There may even still be a virus that has subterfuged your computers protection and is invisible to simple troubleshooting measures. These problems are beyond the scope of this article but may be covered in another article on


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