That's what happens to me and I've followed all the instructions from Microsoft, those on Youtube and the rest of the internet. There have been positive results but the problem persists anyway, especially when I run Malwarebytes or Eset Smart Security. Many say the problem is with the free Windows 10 that comes on the pc, so I'm thinking of buying Windows 10 Pro Retail, hopefully this will be the solution. Regards.

means that the system is writing or reading data to or from the hard disk and is at 100% capacity

If I understand windows correctly, in general a 100% hard disk usage means that you no longer have enough space to run your computer at its minimum capacity.

The suggestion is that you free or delete unimportant information to regain space to return to a possible normal operation.

Most likely your RAM is too small. When you run out of RAM, the system starts storing the information on the hard drive ### which is very heavy on the machine and extremely slow.

Sometimes it's because an update is downloading, a process that doesn't always show up in the task manager. It also happens when your hard drive is saturated, so that every time the PC wants to occupy it, it has to do a lot of operations to find space.