Hi, My first post so I hope I keep to the rules.
A couple of years ago, win 7 64 bit on an old desktop which was like Grandma's broom.
Had had new bigger RAM installed, a new motherboard, a faster CPU and loads of WD Green HDD's.
Worked very well for years and the normal boot sequence was (If I remember right).
Motherboard entered POST (Power on self test)
There was a beep from the motherboard.
The screen showed details of the video card and it's RAM.
The Motherboard Gigabyte flash screen appeared.
Win started normally.
Then it became faulty.
After switch on there was no beep.
HDD's spun up and fans ran but nothing more.
After removing and reconnecting cables to the motherboard and several restarts (I used the power switch to save waiting 4 secs on the power button)
It might then start normally as above.
The problem appeared intermittently.
Eventually it became "stuck" as described it this thread.
So I disconnected all HDD's except for the system disk and BINGO, restart was normal.
I reconnected the HDD's in sequence and found a WD Green 2TB drive was the culprit.
It was a drive used to archive photos and other personal data so it was easy to replace.
Problem gone or so I thought.....
I upgraded to Win 10, even did a clean install.
Win 10 reported another HDD as problematic.
I reinstalled Win 7 and managed to copy all I needed from the HDD and replaced it.
Installed Win 10 again and all fine.
The HDD's are fairly old, some up to 8 years old - maybe they have a reliability "sell by date?"
During this latest phase, I bought a new desktop with a 480Gb SSD, i3 CPU, 16Gb RAM and about 12Tb Hdd's but this time I have gone for the WD Black drives.
The new machine is blindly fast and the i3 is not pushed hard even with video editing and I love it.
During the HDD problem I learned that WD make HDD's and aim to produce the highest quality, however, when they test them some are perfect and sell as Black high speed etc.
Some not able to meet the highest spec sell as Blue, not quite so fast and
finally others sell as Green, rather slow.
Maybe all manufacturers do something like this?
This might not be the problem here but who knows, it happened to me.
Just sayin.
Good luck in diagnosing and fixing.
Intermittent problems are the worst!