Windows 8 100% CPU use idle by disk degragmenter

Hi Larry,

Thank you for posting your query in Microsoft community forums.

I understand the issues that you are facing in Windows 8 computer.

I would suggest you to perform the methods given below and check if the issue persists.

For issue With 100% CPU usage.

Method 1: Try booting the system in safe mode and perform a clean boot.

Step 1: Perform Safe Mode

Click the link and follow the steps “Windows Startup Settings (including safe mode)”

http://windows.microsoft.com/en-US/windows-8/windows-startup-settings-including-safe-mode

Check if you face the same issue in safe mode. If the issue doesn’t persists in safe mode, the place the computer in clean boot and check.

Step 2: Perform Clean Boot.

To help troubleshoot error messages and other issues, you can start Windows 8 by using a minimal set of drivers and startup programs. This kind of startup is known as a "clean boot." A clean boot helps eliminate software conflicts.

http://support.microsoft.com/kb/929135

Important: Reset the computer to start as usual.

Note: After you have finished troubleshooting, follow these steps to boot to normal startup.

a)      Press the ‘Windows + R’ key on the keyboard.

b)      In the ‘Run’ windows type ’MSCONFIG’ and click ‘Ok’.

c)      On the ‘General’ tab, click the ‘Normal Startup’ option, and then click ‘OK’.

d)      When you are prompted to restart the computer, click ‘Restart’.

Method 2:

Download and run Microsoft Safety Scanner from the link to make sure you computer is not infected by virus:

http://www.microsoft.com/security/scanner/en-us/default.aspx

Note: The Microsoft Safety Scanner expires 10 days after being downloaded. To rerun a scan with the latest anti-malware definitions, download and run the Microsoft Safety Scanner again.

Note: Any data files that are infected may only be cleaned by deleting the file entirely, which means there is a potential for data loss.

You have also mentioned that the computer is slow while booting, I would suggest you to repeat Method 1, disconnecting all the external devices connected to computer except keyboard and mouse.

Ways to improve your PC's performance

http://windows.microsoft.com/en-US/windows-8/improve-pc-performance

Windows hangs or freezes

http://support.microsoft.com/kb/2681286

If the issue still persists, please contact your hardware manufacturer for further assistance.

Hope this helps to fix the issue, if you have any further queries, please feel free to post. We are here to help you.