I have had two computers to fix in the last four days. An iMac and a PC laptop The iMac took six hours to find the problem, a dodgy ram chip, and a few hours more to reinstall the whole system from a back up. The PC has so far taken three Days to get to the point where Windows will do exactly what it is designed to do, not drag its heels like a Neanderthal. It seems to be taking a few hours more to install Windows 10. I don't own the PC and have vowed never to touch windows again. Good luck to all who venture. And thanks for letting me get that off my chest, three blooming days!!!!!!!