Windows 10 won't install?

Question

Hard disks

Installation (copying) from a bootable flash drive reaches 34% and the computer restarts, what could be the problem? Could the hdd be faulty?

Answer 1

Windows 10 won't install?

Yes , it is not installed, judging by your description of the situation.
The problem could be anything.
If you want a specific answer, ask the right question.

Answer 2

The flash drive is badly written or the usb port is buggy, try to overwrite another usb too
Problem with the disk
Overheating

Answer 3

And also clean the memory contacts, check the thermal paste, and the power supply can be naughty, or even the capacitors are swollen on the mother. Cable, too, often. In short, a lot of fun.