HP Pavilion x360 won't boot !

[Dudelogical]

I have an HP Pavilion x360 m Convertible (Model is 14m-dh1003dx).
 
When I switch on my laptop, the following message is being displayed --
"Boot Device Not Found
Please install an operating system on your hard disk.
Hard Disk <3F0>
F2 System Diagnostics"

So the following are the 6 troubleshooting steps that I went through ........
 
(1) Firstly, I wanted to check if the hard disk is ok. So I pressed F2 to go into the HP PC Hardware Diagnostics UEFI, and selected the option "Hard Drive Check" . It ran the test for 5 minutes and displayed the following message --
"Smart Check : PASSED
Long DST : PASSED"
 
(2) Then I thought of running the "Windows Recovery Drive" . Which I have on a USB stick, which I made when I bought this computer. So I went into the boot order menu (F10) and made USB Drive the first one. Then switched the computer off, inserted the Windows Recovery Drive USB stick, and restarted the computer. All I see is a black screen with the grey HP circle logo in the centre of the screen, like when the windows is booting up. And there are no circling dots below that logo, only the black screen with the grey circle HP logo in the centre. I left it like that for a long time, but nothing happens.
 
(3) Next I tried running the "Windows Installation Media". Which I had made on another USB stick. With the USB Drive being first on the boot order, I inserted this Windows Installation Media USB stick, and restarted the computer. It doesn't even recognise it. It just displays the original message --
"Boot Device Not Found
Please install an operating system on your hard disk.
Hard Disk <3F0>
F2 System Diagnostics"
 
(4) I even have a "Hiren Boot CD" on a third USB stick. I thought of trying it. Same steps, with the USB Drive being first on the boot order, I inserted this Hiren Boot CD USB stick, and restarted the computer. It doesn't even recognise this one as well, and again it just displays the original message --
"Boot Device Not Found
Please install an operating system on your hard disk.
Hard Disk <3F0>
F2 System Diagnostics"
 
(5) Next I thought of trying the BIOS Recovery/Update. I restarted the computer while press-holding the Windows key+B key, at the same time pressing the power button for 3 seconds. The screen went blank for 10 to 15 seconds, then the following message appeared --
"The BIOS recovery files cannot be found or the files are corrupted.
Using another computer and a USB flash drive, download the latest BIOS file from the HP website and create a BIOS USB recovery drive for the PC that needs recovery.
Insert the BIOS recovery drive into the PC that needs recovery and restart the PC.
To learn more about creating a USB recovery drive, go to the HP website (and then there's a link in blue colour font)"
 
(6) Next, I thought of trying "System Recovery". I pressed the power button to start the computer, and then pressed ESC key repeatedly to go into the Startup Menu. Then pressed F11 (System Recovery option) . It displays the following message in a blue dialogue box --
"The selected boot device failed. Press <Enter> to Continue"
So this did not work as well.
 
An important note -- Ever since I bought this computer, occasionally something used to happen. The computer, while running, would crash, and then restart itself. And then at the time of booting up, it would show this same message --
"Boot Device Not Found
Please install an operating system on your hard disk.
Hard Disk <3F0>
F2 System Diagnostics"
This used to happen occasionally, and been happening ever since I bought this computer. BUT, whenever this happened, I just used to turn it off, then back on, and it used to boot back up normally, and windows started up normally. So I thought it's just an occasional malfunction and didn't think much of it.
 
Please help me resolve this. I am guessing it's the BIOS issue. Should I do the steps mentioned in point 5 that I wrote up here about the BIOS?
 
[P.S. -- I do not know if my Windows 10 is 32 bit, or 64 bit]

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