My son brought this Toshiba C55D to me saying it was slow. I checked the Task Manager and the disk drive was at 98% and the CPU was also at 98 %. I disabled the Avast and stopped the updates. Rebooted and checked again for updates, lots. To make a long story short, it will not start with the Wireless Internet and various other apps so I downloaded on my main computer the Win 10 iso. Put it on a USB stick and tried to install on the Toshiba. It got to 35% and failed. I tried this twice. I took the HDD out and on my machine using an interface I quick formatted the C drive. Reinstalled the drive in the Toshiba and started a Custom install, got partway through and it was looking for drivers. I am in the process of downloading and putting on the same USB stick all the Toshiba drivers.
What am I doing wrong or is this "normal"?

Regards,