Hello, I faced an issue of my recently build PC.

Every time when I switch on PC power and turn on my PC, I hear a short beep once but I managed to boot to Windows and use. But upon restart from Windows, the BIOS will stuck (corner shows A0) and the post LED from motherboard lights up BOOT and VGA. However, if I turn off using case power switch and turn PC on again, it can boot to Windows but with a short beep again.

CPU: AMD R5 5600X
GPU: Zotac GTX 1050 Ti OC
RAM: HyperX Predator 8GB x2
MOBO: Asrock B550M Steel Legend
NVME: Kingston 128GB
HDD: WD Blue 500GB

Did you install Windows using UEFI mode?

Yes

Can you disable XMP and try again?

Might be a memory training issue

Also, did you install Windows with the HDD disconnected from the system?

This post has been edited by chocobo7779: Jan 29 2021, 05:30 PM

Asrock B550M Steel Legend has 4 post status checker LEDs for diagnostics.

• CPU (labelled CPU on the motherboard)
• Memory (labelled DRAM on the motherboard)
• VGA (labelled VGA on the motherboard)
• Storage (labelled BOOT on the motherboard)

When the system cannot boot up, you mentioned BOOT and VGA LEDs lights up. Do they stay light up until you power cycle?

BOOT - Most probable cause:

• Your NVME drive loose connection to the socket. Assuming this is your OS drive.
• The system cannot find the bootloader.

Solution:

• Enter BIOS and check in the boot menu if it was able to find the UEFI installed OS on your NVME drive?

VGA LED light up is a strange case. If this lights up, are you able to check if your monitor show anything on the screen, like boot up picture?

Also, what is the exact part number of your memory modules?

This post has been edited by SFX: Jan 29 2021, 05:30 PM

Yes, the LEDs do stay light up. I can see my NVME drive and "Windows Boot Loader" is there. When the system can't boot, it just stuck at the boot up picture there (Asrock logo), F2 can't enter BIOS also, need to switch off then on again to go in Windows.

Edit: The RAM is HX432C16PB3AK2/16

This post has been edited by igx0908: Jan 29 2021, 05:42 PM

Disabled XMP but it's the same. Normal boot can go Windows but when reboot stuck at BIOS. I install Windows with HDD connected, is this gonna be an issue?

Yes, as Windows may install the Boot Manager on the HDD rather than the SSD

Also, did you disable CSM in the BIOS?

This post has been edited by chocobo7779: Jan 29 2021, 06:05 PM

I disabled CSM and try again but still the same. I checked Disk Management and my HDD only have 2 data partitions I'm currently using.

Your memory modules is in the qualified list.

When it stuck at the boot up picture (Asrock), does the post status checker LED light up? The way you describe the issue lead me to think that something is wrong during the POST of the motherboard.

What is the BIOS version of your motherboard? Latest version released was 1.80 (10/12/2020).

Windows 10 installation? Can you check if it is in UEFI mode?

Also, can you please screenshot your disk manager?

Yes, the post status checker LED light up when stuck.

BIOS version is 1.80.
Windows 10 in UEFI mode

I hit F2 when it was stuck in BIOS, and about 5 minutes later, I was in the BIOS. I checked and were able to see my onboard devices (HDD and NVME) listed but now "Windows Boot Manager" is missing. Strange because this only happens on every restart from Windows and/or coming out of BIOS.

Booting from shutdown is not a problem although there's a short beep.

This post has been edited by igx0908: Jan 29 2021, 06:47 PM

This narrows down the issue when the post status checker LED light up when stuck. Was it the same BOOT and VGA LEDs both light up at the same time when it stuck?

We are going to perform some experiments to find out the root cause:

Experiment 1
For this experiment, please disconnect both NVME and HDD. Do multiple boot ups and check if it still stuck at the POST screen? And when it stuck, what are the LEDs that light up?

If it get past the "stuck" stage and it cannot find the OS to boot up, that is fine because you don't have any storage (NVME or HDD) connected.

Experiment 2
Please move your graphic card to the second PCIe slot. Do multiple boot ups and check if it still stuck at the POST screen.

When you say Boot Manager is missing, possible it is just not selected as first boot, but still can change to select it as first boot?
Or totally don't have?

My feeling is that when restart the mobo switch to backup bios and some of the setting is incorrect.

Experiment 1 straight boot to BIOS. Experiment 2 is the same results.

It is the only boot option set. The rest I had disabled.

So, experiment 1 and 2 both able to boot into BIOS successfully and repeatedly, i.e. Power down, boot up, able to go into BIOS, not "stuck" multiple times? What does the LED indicators show?

How many times did you try it? Can you try it 20 times?

This post has been edited by SFX: Jan 29 2021, 11:31 PM

My bad, for experiment 2, I faced the same issue as before, I can go to Windows but when restart in Windows, I will then stuck in BIOS again until I power cycle it or wait for 5 minutes and let it go inside BIOS . Sorry...

Now that I re-read your problem statement, I am now thinking that it is not a hardware issue, but rather the OS behaviour causes it to behave erratically. It was mentioned in your very first post and I didn't notice it until your latest post, which makes me try to understand the problem description carefully.

Let me know if I'm reading your problem faced correctly.
1. Switch on power to your PC → Press power button on your computer chassis → Motherboard POST successfully → Load Windows 10 → Able to go into the desktop.

2. From Windows 10 itself → Press Start -> Power -> Restart → System goes to restart (with Restarting... wording) → Unable to go past BIOS' POST stage, hence "stuck"?

If my understanding and I describe the problem statement correctly, then it could be problem with the OS and drivers interaction.

In 1., Windows 10 (and 8) implement something called Fast Startup feature. When you shutdown your PC from the Start Menu, Power, Shutdown route, Windows transferred the RAM contents to storage (NVME/HDD). The next time you start up your PC again, it just read back the written file and put it back to RAM and boot up from there.

In 2. however, if you restart your PC via the Start Menu, Power, Restart route, it power down the system and then power up. After it power up, during the booting process, it actually reload Windows kernel and all the driver files from scratch (i.e. it didn't use that file mentioned in 1.)

Solution
1. Open up command prompt in administrator mode and run sfc /scannow to fix Windows files. Restart like how you do in 2. and check if it works.
2. Driver for your components could be an issue. Start -> devmgmt.msc and check if there is any issue with any of the hardware components you installed. Updating the drivers could probably help.
3. Reset Windows 10, a new feature that will reinitialise your system from scratch without reinstalling the OS. Last option if solution 1 and 2 doesn't work.

This post has been edited by SFX: Jan 30 2021, 01:45 AM

I reinstalled Windows without HDD plug in, still cannot. Somehow Windows Boot Manager will disappear on every reboot

This post has been edited by igx0908: Jan 30 2021, 11:08 PM