iFixit - Answers With Device "HP EliteBook 840 G3"

HP EliteBook 840 G3: Laptop not turning on

Mon, 29 Dec 2025 16:06:02 -0700

Okay lately my laptop has not been turning on but the fan was spinning really loud and fast as usual they say it's bad ram I thought so too but when I replaced the ram it still did not work and I also experimented my ram on another laptop and it worked perfectly

So now I really don't know what's the problem can you guys help me

⟐ Commented December 29, 2025 at 16:06 MST

HP EliteBook 840 G3: Windows 11 software upgrade. From 10 to 11

Sun, 19 Oct 2025 22:36:13 -0700

Can I run windows 11 on my hp elitebook 840 g3

⟐ Answer edited October 19, 2025 at 22:36 MST

HP EliteBook 840 G3: Booting device not found 3FO error

Thu, 25 Jul 2024 06:35:09 -0700

All of the sudden my pc is not opening it is saying booting device is not found... I tried to get in to bios and try to fix it but it's asking me bios administration password and I don't know it.

Am a student and I need help as soon as you can, exam is around the corner.

Thank you for your time.

⟐ Commented July 25, 2024 at 6:35 MST

HP EliteBook 840 G3: No display, with fan running at top speed

Fri, 09 Aug 2024 23:04:08 -0700

When I start or plug inthe laptop the lights turn on with no display. After that the CAPS and NUMS lock blinks exactly 5 time and then the fan runs at top speed. I have tried the bios reupdate, cleaned the rams and SSD. I even tried to change these and removed the cell on the mother board with 30 secs of pressing power button

⟐ Answered August 09, 2024 at 23:04 MST

HP EliteBook 840 G3: My laptop is not turning on

Wed, 03 Sep 2025 15:03:49 -0700

One day, I left my laptop turned on on the table and when I came back the other day, I wasn't able to turn it on.

When I press a start button, nothing happens. The screen is black, the white led diode does not light up and the fan is not spinning either. I tried a full power refresh but it didn't help.

I do not know what to do, can you help me please?

⟐ Commented September 03, 2025 at 15:03 MST

HP EliteBook 840 G3: The screen aint working...its black screen and doesnt light up jus be

Thu, 24 Apr 2025 15:04:05 -0700

My laptops screen is black even after powering and plugging in the adapter.it beeps alot too but doesnt power on,just a boack screen..what can be the issue?

⟐ Edited April 24, 2025 at 15:04 MST

HP EliteBook 840 G3: How To Fix Dark Screen Laptop?

Tue, 05 Sep 2023 03:43:54 -0700

How To Fix HP Black Screen - Computer Starts But No Display - Screen Not Working

⟐ Commented September 05, 2023 at 3:43 MST

HP EliteBook 840 G3: Beeping and not turning on

Thu, 24 Aug 2023 00:10:41 -0700

Laptop is beeping 3 times and stop and beep 2 times again for 5 or 6 times

⟐ Answered August 24, 2023 at 0:10 MST

HP EliteBook 840 G3: How to replace base enclosure

Tue, 18 Jan 2022 07:59:50 -0700

how do I replace my base enclosure

⟐ Answer accepted January 18, 2022 at 7:59 MST

HP EliteBook 840 G3: Why is my laptop not taking charge

Sat, 16 Dec 2023 14:10:43 -0700

My laptop isn't taking charge and the charger is flashing green light

⟐ Commented December 16, 2023 at 14:10 MST

Hp elitebook 840 g3: Battery dies often after replacement

Sat, 13 May 2023 00:19:18 -0700

Hp 840 has been killing batteries. Replaced severally and it dies in a few months. The problem is gradual as it descharges it gets to a percentage like 40 and goes off, then 60, 70 100. When you disconnect from power it shuts. What's the problem and solution to it?

HP EliteBook 840 G3: Power button not working after BIOS chip replacement

Tue, 07 Feb 2023 12:40:18 -0700

I have just replaced my BIOS chip in 840 G3 (dreaded forgotten BIOS password). After mounting the new chip, I reassembled as usual, but there is absolutely no response from the power button. I replaced chip the usual way with a 400C heat gun and I believe it went well.

Any ideas appreciated

Thanks

⟐ Edited February 07, 2023 at 12:40 MST

HP EliteBook 840 G3: Some Keys of Keyboard is Not Working

Mon, 03 Nov 2025 03:44:44 -0700

On my laptop, some keys on my keyboard are not Working. I installed Windows and troubleshooted the keyboard, but still, the problem is not resolved. Please Help me to resolve the issue

⟐ Answered November 03, 2025 at 3:44 MST

HP EliteBook 840 G3: My laptop turns on but it doesnt boot

Sat, 09 Aug 2025 03:45:38 -0700

I was using my laptop and it suddenly show the orange screen error message and didnt reboot so i manually it off and now it doesnt boot. When i turn it on or try to turn on it just shows the hp logo and stops there i tried going to bios after turning it on buh the it doesnt even boot the bios and then diagnosis said it couldnt see the hard drive buh my hard drive is still in it.

⟐ Commented August 09, 2025 at 3:45 MST

HP EliteBook 840 G3: My display is glitching

Thu, 03 Jul 2025 22:31:44 -0700

I don't know if the problem is with the display or the RAM I will try to connect a external monitor later. When I am using the laptop while glitch screen it seems to get worse but it doesn't seem to compromise with the performance I hope it is an easy fix i think it's the problem with the display because few days ago I was carrying the laptop in my bagpack which was heavily packed

⟐ Answer edited July 03, 2025 at 22:31 MST

HP EliteBook 840 G3: HP EliteBook 840 G3 Hard Disk - (3F0)

Mon, 12 Aug 2024 17:42:24 -0700

Model: HP EliteBook 840 G3

System BIOS: N75 Version 01.61 10/03/2023

OS: Windows 10 Professional x64

16GB RAM

256GB 2.5" SSD (Detected in BIOS)

Error

Testing Drive: 1

SMART Check: SOFTWARE ERROR

Short DST : NOT AVAILABLE (1: NOT AVAILABLE)

Error After Restoring BIOS to factory

BootDevice Not Found

Please install an operating system on your hard disk.

Hard Disk - (3F0)

F2 System Diagnostics

I received this exact error almost 2 months ago so I replaced the hard drive with a solid state drive, installed the operating system and was using it fine for about 7 weeks. Today, it's giving me the exact same error. I've gone into the BIOS, restored to factory and restarted, but same result. Any help is much appreciated.

⟐ Answered August 12, 2024 at 17:42 MST

HP EliteBook 840 G3: it turns off by itself with in 10 minute duration

Tue, 31 Oct 2023 23:47:40 -0700

my pc turns by itself and can not start until i plug it and it will turn off again with in 10 to 20 minutes if i unplug it but it has a battery percentage of 80%

⟐ Answered October 31, 2023 at 23:47 MST

HP EliteBook 840 G3: My pc takes forever to start, although it has SSD, and it lags a lot

Sun, 04 Jun 2023 02:12:30 -0700

I have an Hp computer that used to work just fine, until recently, it takes about 2minutes to turn on when it used to turn on fast, plus when im using it it suddenly lags and i cant use the mouse or move anything when that happens, I turn it off and on to fix, I don't understand what is the issue.

this is my Pc's info:

⟐ Answered June 04, 2023 at 2:12 MST

HP EliteBook 840 G3: ( it actually a elite desk 800 g3 mini 35w

Sat, 11 Feb 2023 09:37:46 -0700

watch this and if need more detail let me know also I have used jumper too

⟐ Answered February 11, 2023 at 9:37 MST

HP EliteBook 840 G3: Screen get black with snow

Mon, 15 Feb 2021 14:47:27 -0700

Hi,

I’ve a 5 years old HP EliteBook 840 G3 and with an irregular frequency, screen get black with some rectangles within there are snow (like when old TV lost their signal). I’ve heard that some MacBook get same behavior and the problem is in the RAM slot. Could it be possible that my laptop has the same problem? How can I verify and be sure that’s exactly that problem? Can I repair it? Or do I have to replace all the main board?

I checked my RAM with memtest and my SSD with SMART and there were nothing to be alarmed about. I’m running on Manjaro and I found nothing in the log files.

Thank in advance for your help.

⟐ Answer accepted February 15, 2021 at 14:47 MST