Laptop won't switch on, power button and num lock are flashing

[Em1806]

My computer froze. I turned it off by holding down the power button, when I turned it back on it got stuck on the booting page, so I held down the power button again. Now when I try turning it on, the screen stays black and the power button and num lock buttons are flashing. I tried doing a hard reset (holding power button for 15 secs) but it didn't solve the problem. 

[Dragon-Fur]

@Em1806 

Something has indeed failed.

Readers with Notebook computers:

HP Notebook PCs - Computer Does Not Start (Windows 10)

and

The Dreaded Blinking light condition.

Document explains the codes and "blinks":

HP Notebook PCs - Computer Does Not Start and Emits an LED or Beep Code

TKB Article contributed by HP Wes_notebooks 

Testing for Hardware Failures

Device Home Page - References and Resources – Learn about your Device - Solve Problems

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Categories:  Alerts, Warranty Check, HP Drivers / Software and BIOS, How-to Videos, Bulletins/Notices, How-to Documents, Troubleshooting, User Guides / Manuals, Service and Maintenance Guide (Replacement Parts and Procedures), Product Information (Specifications), more

When the website support page opens, Select (as available) a Category > Topic > Subtopic

HP EliteBook 850 G3 Notebook PC

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[Em1806]

Thanks. Weirdly about 10 minutes after posting my message, the laptop made a loud beeping sound then switched on as normal. All seems OK so far. Should I have it checked over? 

[Dragon-Fur]

@Em1806 

You are welcome.

Well, there you go.

It almost sounds like it was an interrupted BIOS update session - these "beep" quite loudly in an attempt to get the operator's attention.  This is just a guess, of course.

If, for example, you still use HP Support Assistant as your Update software and if you have left that software set to Automatic Updates / Installations, you never know when / what will be suddenly updated.  The BIOS update is one of the updates that can startle, hang, die in these circumstances - the HPSA doesn't always do a good job with BIOS updates - just one hiccup in this area can produce a variety of weird results.

Whether you have the machine checked is up to you - people tend to move on from unexplained - but satisfactory - adventures.

Not to "fix" - Use to observe what the system thinks is going on - use the Reliability Report Monitor.

Reliability Report

Although this cool reporting tool has been around for quite a while, it might be overlooked because it is hiding in an unlikely spot in the Operating System.

Windows 7:

Control Panel > set icon view > Action Center

Windows 10:

Control Panel > set icon view > Security and Maintenance >

Under Maintenance > Open the Drop Down Menu >> Click on View Reliability Report

Method to start the Reliability Report software using Command Prompt

Open Admin cmd prompt

Windows key + X + (then) A

Type the command, followed by the "Enter" key

perfmon /rel

Create Reliability Report Shortcut:

Navigate to C:\Windows\System32

Right-Click perfmon.exe > Send to Desktop

Right-Click on shortcut in Desktop > Properties >

Add “ /rel” to target line (space in front of /rel):

Target (path) = C:\Windows\System32\perfmon.exe /rel

Tab General > Change name as desired

OK

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