I have a hp dv6 i5 1TB hdd laptop that first came with windows 7 pro. never had a problem except for updates, all fixed.
in late 2018 I upgraded to windows 10 64 bit pro. I got drivers to suit from hp along with a bios upgrade.
from the first restart this problem appeared. the sequence is:-
hp start up screen ok. windows logo and dots circle running for 5-10 seconds, then screen blanks out for 45 to 70 seconds, lots of hdd activity, then screen comes back on to logo and circle for a few seconds then the logon screen. from this point all works just fine.
if you do a cold start the same sequence but the blank screen is longer than restart.
if you do a safe mode then the blank screen is only a few seconds.
I have rebuilt the laptop a number of times, with and without drivers, different hard drive, different copy of both drivers and windows 10 pro all exactly the same results, re loaded windows 7 perfect.
tried 32 bit version of 10 and still this blank screen. now back to 10 64bit pro as i need.
any ideas as to what i have wrong. please
i even tried a second hand mother board and a new ssd drive..... the ssd is faster but blank is still the same.
Screen blanks then reapears later during boot on windows 10 fine with windows 7