A possible helpful tip.....
I'm working on some older computers, upgrading them putting legit windows 7 on them and selling them off cheaply to people who need them. These last two (a laptop and desktop) both were clean installed and yet the CPU usage was constantly at 100% and the computers would hang. Took nearly a day of investigating, but I found that stopping Windows Update service sent them back to normal, then I disabled IPV6 protocol and on a restart of the service (and computer) they were behaving much better. CPU usage up and down, not pegged.
also install KB3102810
Not sure is this will be helpful to anyone, but it might save you some google headaches.....