Now we are looking for a boot problem and high disks loads and a battery problem? That makes it extremely difficult.
Try isolating one problem and stick to that.
Boot problem
You could try booting up in save mode, so you won't be hindered by cloud - and other services.
Than I would suggest installing all W10 drivers from the HP support site, and so minimizing the possibility of a driver problem.
Reboot still in save mode. If the boot problem still exists, rerun the tests of Neemobeer answer #3
Disk loads
You could try creating a new account. Log on to that account and see what happens with the disk load. If it is still high you have a Windows problem, but if it is low it is one of your processes.
That is all I can think of, hope it helps a little bit.