Windows start failure on hp probook 450 g2

[Idrismca]

1. Product Name and Number hp probook 450 g2

2. Operating System installed (if applicable)
•  Windows 10
3. Error message (if any) 
Inaccesible Boot device
4. Any changes made to your system before the issue occurred
no changes were made but i went through all possible options and did a lot of research but nothing worked.

a. hard reset

b. safe mode

c. chkdsk

d. recovery

e. previous back up point

f tried to to copy system, etc regback in D:\windows\system32\config

but no files were present in regback

everytime i restarted the laptop it would give me inaccesible oot drive and then

"D:/Windows/System32/LogFiles/srt/SrtTrail.txt"

thats when i tried to follow these steps i found online

x:\windows\system32\config\regback> bootrec /fixmbr

that step worked

then i ran bootrec /fixboot

but it gave me access denied so i ran

1. diskpart

2. sel disk 0

3. list vol

4. set vol 1

5. assign letter= V:

6. exit

7. bcdboot

D:\Windows /s V: /f UEFI

then performed below steps

 1. cd /d V:\EFI\Microsoft\Boot\

2. bootrec /FixBoot - but it again gave me access denied,,, i still went ahead with other steps

3. ren BCD BCD.old

4. bcdboot c:\Windows /l en-us /s V: All

5. bootrec /rebuildbcd

6. exit

now after restart it doesnt give me any options but just start up settings from F1 to F9 and i tried all but nothing works.

I dont mind loosing all my work but just want the laptop to start again with proper os.

Please help

[Lil_Boy_Blue]

Hi

Personally I use Linux Mint Live to solve such problems with inbuilt Gparted.

The BIOS is correct?  No discharged CMOS/RTC battery?

Could the dirty bit be set?

I may be covering old ground, but please be tolerant...

https://www.windowscentral.com/how-clean-and-format-storage-drive-using-diskpart-windows-10

OR (hope this helps)

diskpart

listdisk

select disk 0

clean

list disk
create partition primary
select partition 1
active
format FS=NTFS label=Data quick
assign letter= ???????????
exit
exit