Disk at 100% usage

In Task Manager, on the Processes Tab

If you click on the Disk column header so the arrow is facing down

What processes are at the top (using the disk the most)?

Take a look at this article

WIN10 100% DISK USAGE PROBLEM
https://www.kapilarya.com/fix-windows-10-100-pe...

Open Start, type: problem reports
Hit Enter
If there are any pending reports or failed reports, delete them

If you are running the latest version of Windows 10 - open Start > Settings > Update & security > Windows Update > Advanced Options > Delivery Optimization

Make sure Allow downloads from other PC's is toggled off.

Also see:
https://www.groovypost.com/howto/stop-whats-rev...

Also, if you have the Intel Rapid Storage Technology driver installed, uninstall it.

IRST, which stands for Intel Rapid Storage Technology, is a storage driver developed by Intel for use with a variety of storage configurations; such as RAID (redundant array of inexpensive disks) and SATA drives. Modern operating systems such as Windows 10 no longer require IRST driver and can manage such configurations out of the box.

AHCI which stands for Advance Host Controller Interface has been supported out of the box since Windows Vista. If you happen to have Intel Rapid Storage Technology driver installed, you can uninstall it to see if it improves stability. If there is a specific reason you need to keep IRST, then you can try updating it using either the Intel Driver Update Utility or download the latest IRST driver manually and install it. You should check the manufacturers website for your computer model for the latest IRST.

How to uninstall IRST:

Press Windows key + X
Click Apps and Features
Scroll down then select Intel Rapid Storage Technology, right click it then click uninstall.

We are volunteers willing to help you try to resolve this issue.

In Task Manager - click the top of the Disk column - for those process using the most click the little arrow on the very left side of that process it there. Do the same for the CPU column. Process Explorer and Process Monitor might reveal even more details.

If using an SSD or hybrid hard drive be sure it has the latest firmware.

Try the Clean Boot method to see if a startup program is involved - if so it is a process of elimination :

Right Click the start button - Command Prompt (Admin) OR Windows PowerShell (Admin) - at the prompt type in

MSCONFIG

and hit enter

How to perform a clean boot in Windows
https://support.microsoft.com/en-us/kb/929135

Other programs to help :

Autoruns - Free - See what programs are configured to startup automatically when your system boots and you login. Autoruns also shows you the full list of Registry and file locations where applications can configure auto-start settings.
http://technet.microsoft.com/en-us/sysinternals...

Process Explorer - Free - Find out what files, registry keys and other objects processes have open, which DLLs they have loaded, and more. This uniquely powerful utility will even show you who owns each process.
http://technet.microsoft.com/en-us/sysinternals...

Process Monitor - Free - an advanced monitoring tool for Windows that shows real-time file system, Registry and process/thread activity. It combines the features of two legacy Sysinternals utilities, Filemon and Regmon, and adds an extensive list of enhancements including rich and non-destructive filtering, comprehensive event properties such session IDs and user names, reliable process information, full thread stacks with integrated symbol support for each operation, simultaneous logging to a file, and much more. Its uniquely powerful features will make Process Monitor a core utility in your system troubleshooting and malware hunting toolkit.
https://docs.microsoft.com/en-us/sysinternals/d...

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If you had a 3rd party antivirus on the OS you upgraded OR if you have one now uninstall it and then run its maker's removal tool. Use Windows Defender which in Windows 8/8.1/10 is a full antivirus. Despite all the hype out there Windows Defender and the Windows Firewall are true superstars.

List of anti-malware program cleanup/uninstall tools
http://answers.microsoft.com/en-us/protect/wiki...

Uninstallers (removal tools) for common antivirus software
http://kb.eset.com/esetkb/index?page=content&am...

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Check this :

Right Click Start button - Control Panel - Troubleshooting - on right side click View all - System Maintenance.

Please let us know the results and if you need further assistance.