HP ProBook 450 G4 won't boot

[oara17]

This notebook most of the time would hang up at the Restarting screen  and had to be turned off by hard reseting by pressing the power button until the power went off. It started doing that in May 2017, after about 6 months of use.

Tried a solution found on Microsoft forums that the HP fingerpint device could be the problem and it should be disabled. It worked sometimes, but not always. But I found a Windows 10 driver update for the biometric device and installed it, which seemed to work. Then I checked for updates for the display driver and found one but, after installation, the notebook again hung up on Restarting. 

After the usual hard reset, the machine first booted to an HP logo but never got past it. Tried a hard reset again but now it only shows a black screen, although the keyboard lights, the power light, the speaker light come on white, and the Wifi light is amber. The Caps Lock and Num Lock LEDS blink twice and the fan starts. 

Following HP guided solutions, I first tried a power reset for notebooks with non-removable batteries, which didn't work. I also found out that the LEDs blinking twice indicates a corrupt BIOS, so I tried the HP guided solutions Windows key + B combination at boot, to recover the BIOS,  but it doesn't work. 

In any case, for this notebook released after 2015 (made in August 2016,) the blinking codes should only work with the CapsLock LED, not the Caps+Num Lock LEDS, although those LEDs only blink white, not red. So it's not clear what the blinking means.

If the binking codes are misleading and the problem is other than BIOS related, one detail that needs to be mentioned is that the battery light turns on white when the AC charger is first connected but then it turns off after a few minutes, event though the charger is plugged in. So, could it be a battery/charger issue + BIOS issue? or is the BIOS issue affecting the charging operation?

I would like to try the BIOS recovery from a USB drive, but the BIOS download installation has the "Create BIOS recovery  flash drive" option greyed out. I found the latest BIOS here

http://ftp.hp.com/pub/softpaq/sp85001-85500/sp85232.exe

If the problem is BIOS corruption I would really like to try the BIOS recovery before sending the notebook for repair. How can I create the recovery flash drive?

If that option won't work, how can I send this unit for HP repair? It's out of warranty, but it may be worth to fix it. It has a Core i7 processor with 16 GB RAM and 256 GB SSD.

Thanks in advance for any suggestions.

[CF4]

Hi

Do you have the capability to make a Windows 10 Repair/Rebuild/Recover/Re-Install disk using the Microsoft Creator Tool?

2 USB sticks and USB ports to suit on the Laptop?

https://www.microsoft.com/en-us/software-download/windows10

If so it should be possible to accept the agreement and put the files into an area that HP did not choose, like my S:\SP85232 Directory I made.

S:\>cd sp85232

S:\SP85232>dir
 Volume in drive S is StorageArea
 Volume Serial Number is A8E1-438A

 Directory of S:\SP85232

19/04/2018  11:23    <DIR>          .
19/04/2018  11:23    <DIR>          ..
08/09/2017  07:04         4,800,000 HPBIOSUPDREC.exe
19/04/2018  11:26             3,285 HPBIOSUPDREC.log
08/09/2017  07:06         6,692,864 HPBIOSUPDREC64.exe
08/09/2017  07:07         2,287,104 HpqPswd.exe
08/09/2017  07:08         3,128,832 HpqPswd64.exe
30/01/2018  14:19         9,437,184 P85_0115.bin
30/01/2018  12:49         9,437,184 P91_0115.bin
               7 File(s)     35,786,453 bytes
               2 Dir(s)  185,714,126,848 bytes free

S:\SP85232>

Then copy onto a USB stick.

If in doubt please ask.

[oara17]

Thank you CF4 for your suggestion. I did try it, but the notebook just ignored the flash drive.

But I succeeded in creating the recovery drive using the earliest BIOS version for this model. But again, the machine just ignores it when booting with the Windows key + B combination. In fact, while booting in this mode, the Caps/Num Lock keys still blink twice.

So it would seem that there are other hardware issues besides a possible BIOS corruption. However, the blinking codes don't point to anything other than BIOS. For example, the backlit keyboard lights up at power on and dims after 5 sec. exactly as it was configured in the BIOS, so this might mean only partial corruption, e.g. the DXE or main area only? 

In my original post I also mentioned that the blinking codes I see should not apply to this post-2015 release model, and that I see the battery LED not staying on when the AC adapter is plugged in. Any thoughts about these two symptoms?