HP EliteBook 840 G6 Not Turning On: Fixed

Laptop charging light on but it will not turn on? It is not always the end. A local business in Miles Platting brought us their HP EliteBook 840 G6 with exactly this problem: the charging light glowed, but pressing the power button did nothing. The culprit turned out to be corrupted BIOS firmware, and reflashing the BIOS with a known-good image brought it fully back to life. Here is what happened, and what it teaches you about any laptop that has power but no life.

What came in: power but no life

This was a classic, frustrating fault. The HP EliteBook 840 G6's charging light was on, confirming it was getting power, but there was no response at all when trying to switch it on, no fans, no screen, nothing. We collected the laptop from the client's office the next day and got to work diagnosing why a machine that was clearly receiving power simply would not start.

It is worth pausing on how unsettling this fault is for the owner. There is no dramatic clue to go on. No burning smell, no cracked screen, no dropped-down-the-stairs story. The laptop looks perfect. The light says power is reaching it. And yet it sits there like a brick. For a business, that ambiguity is the worst part, because you cannot tell from the outside whether you are looking at a five minute fix or a write-off. That is precisely why a methodical diagnosis matters more than a hopeful guess.

How we fixed it

We opened the laptop and examined it carefully. There was some minor dust inside, but nothing that explained a complete failure to power on. Drawing on experience, we suspected the BIOS, the firmware that brings the laptop to life and manages its hardware before the operating system loads. If that firmware becomes corrupted, the laptop can fail to start at all, even with power present. We carefully reflashed the BIOS with a clean firmware image, a delicate but non-invasive procedure, and on pressing the power button the laptop roared into life. A fault that can otherwise mean a costly motherboard replacement was solved by reprogramming the firmware, with no soldering or board-level work involved.

To be clear about what reflashing the BIOS actually involves, because it sounds more mysterious than it is: the firmware lives on a small dedicated memory chip on the motherboard. When the data on that chip is damaged, the machine cannot run the start-up code it depends on. Using a small clip that clamps onto the chip and connects to a programmer and software, a clean, correct copy of the firmware for that exact model is written back over the corrupted one. This is done without any soldering and without removing parts from the board. Done properly, with the right settings and the right firmware image, the chip wakes up with healthy instructions and the laptop behaves as if nothing ever went wrong. The skill is in matching the correct firmware, reading and writing it safely, and verifying the write afterwards. To be plain about our limits: this is firmware reprogramming, not board-level or soldering repair, which we do not carry out.

What actually is the BIOS, and why does it matter?

Before the screen ever lights up, before Windows appears, a piece of software has already been hard at work. That software is the firmware, historically called the BIOS (Basic Input Output System) and on modern laptops more accurately called UEFI. According to Wikipedia's overview of the BIOS, it is a type of firmware that performs hardware initialisation during the booting process and then hands over to the operating system. In plainer terms, it is the very first thing your laptop runs when you press the power button.

Its job in those first couple of seconds is enormous. It runs the Power On Self Test (POST), which identifies and checks the core hardware: the processor, the memory, the storage, the keyboard and so on. Only once that check passes does it look for an operating system to load. The newer UEFI standard, described on Wikipedia's UEFI page, does the same essential job with more security and flexibility, and it is what nearly every modern business laptop, including the EliteBook 840 G6, actually uses. People still say "BIOS" out of habit, and we do too in this article, but UEFI is the modern reality.

The important point for a no-power fault is this: that firmware is stored on a physical chip. Both Wikipedia references confirm it lives on rewritable flash memory on the motherboard, most commonly an SPI flash chip. Because it is rewritable, it can be updated, which is useful. But because it is rewritable, it can also be damaged. And if the very first instructions your laptop needs to read are scrambled, the machine never gets far enough to show you a screen, let alone an error message. It simply does nothing, exactly like our Miles Platting EliteBook.

How does a BIOS actually get corrupted?

If firmware is so important, you might reasonably ask how it ends up broken in the first place. There is rarely a single dramatic cause. More often it is one of a handful of everyday situations:

• An interrupted firmware update. This is the classic one. If a BIOS or UEFI update is running and the power is cut, the battery dies, or the machine is forced off mid-write, the firmware can be left half-written and unusable. Wikipedia notes that an improperly executed or aborted update can render a device unusable, which is exactly the risk.
• A sudden power loss or unstable power. A power cut during a critical moment, a failing battery, or a dodgy charger can interrupt the firmware while it is being accessed.
• Flash memory wear or a marginal chip. The memory cells that hold the firmware do not last forever. After years of use, a cell can fail to hold its data reliably, leaving a small but fatal error in the stored code.
• Malware. A small number of sophisticated threats deliberately target firmware, because code that runs before the operating system is very hard to detect and remove.
• A bad sleep or wake cycle. Occasionally a laptop that is repeatedly forced off during sleep or shutdown can corrupt settings stored alongside the firmware.

In our EliteBook's case, the exact trigger was less important than the outcome: the stored firmware was no longer valid, so the machine could not start. The cure was to put valid firmware back. If you want a deeper read on the firmware itself and why updating it carries both benefits and risks, our guide on whether you should update the motherboard BIOS covers it in detail.

Why won't a laptop turn on even when it's charging?

A charging light tells you the laptop is getting power, so when it still will not start, the fault lies somewhere between that power and the machine actually booting. Common causes include corrupted BIOS or firmware (as here), a faulty power button or its connection, a RAM or component issue, or a deeper motherboard fault. Because a charging light rules out the obvious power problems, these cases need proper diagnosis rather than guesswork.

Before assuming the worst, a couple of simple steps are worth trying at home: disconnect the charger and any peripherals, hold the power button down for 30 seconds to discharge residual power, then reconnect the charger and try again. If that does not work, the fault is internal, and as this repair shows, it is often fixable without replacing the whole motherboard or laptop. Our guide on the BIOS explains more about this crucial firmware.

It helps to think of it as a chain. Power has to arrive (the charging light), then it has to be converted to the various lower voltages the components need (the motherboard's power circuitry, often called the power rails), then the firmware has to run, then the hardware has to pass its self test, and only then does the operating system load. A break anywhere along that chain stops the laptop, but the symptoms differ depending on where the break is. The skill in diagnosis is reading those small differences to work out which link has failed before touching a screwdriver.

What the symptoms are quietly telling us

No two no-power faults present in exactly the same way, and the small details are genuinely useful clues. Here is how we read some of the common patterns:

None of this replaces a proper bench diagnosis, but it shows why "it won't turn on" is never one single fault. Two laptops with identical symptoms can need completely different fixes, which is why we never quote a one-size repair price down the phone for a dead machine.

The no-power checklist you can safely try at home

Before any laptop comes to us, there are a few safe steps worth trying yourself. None of these involve opening the machine, and they fix a surprising number of "dead" laptops that were simply confused rather than broken. Work through them in order:

• Do a hard reset (a power drain). Unplug the charger, remove any USB devices, SD cards and accessories, then hold the power button down for about 30 seconds. This discharges residual power held in the machine and clears a temporary stuck state. On older laptops with a removable battery you would take the battery out first; the EliteBook 840 G6 has an internal battery, so the press-and-hold method is the right approach.
• Test the charger and the wall socket. Try a different, known-good socket. If you have a compatible charger to hand, try that too. A failed charger or a tripped socket can perfectly mimic a dead laptop. If your charging light never comes on at all, our guide on a laptop battery that will not charge is the better starting point.
• Leave it on charge for a while. If the battery is completely flat, some laptops need 15 to 30 minutes on the charger before they will respond at all. Plug it in, leave it, then try again.
• Try with the charger connected. A laptop with a failed battery can sometimes still power on from the mains. If it boots on the charger but not on battery, you have learned something useful.
• Listen and look closely. When you press power, is there any fan movement, any click, any flicker of a light or the keyboard backlight? Note what does and does not happen; it genuinely helps whoever repairs it.

If you have worked through all of that and the machine still will not start, the fault is internal. That is not bad news. As this repair shows, internal faults are frequently fixable, and often for far less than you fear.

HP Sure Start: why EliteBooks usually heal themselves

There is an interesting twist with HP's EliteBook range specifically. These business laptops include a feature HP calls Sure Start, which is a self-healing BIOS protection system. In normal operation it keeps a verified, hardware-protected backup copy of the firmware. Every time the laptop starts, it checks the active firmware against that golden copy, and if it spots corruption it can quietly restore the clean version, often before you even see a screen.

So why did our EliteBook not heal itself? Self-healing systems are excellent, but they are not infinite. If the backup copy is also affected, if the corruption sits outside what the recovery routine can reach, or if the hardware that performs the recovery cannot complete the process, the safety net does not catch the fall. That is exactly when reflashing the firmware directly with a known-good image, using a clip and software rather than any soldering, becomes the right tool. The lesson is reassuring rather than alarming: business laptops are built with multiple layers of protection, and when those layers are exhausted, a skilled repair is still very often possible.

Reflashing the BIOS versus replacing the motherboard

Here is where real money is saved or wasted. When a laptop will not power on, the lazy diagnosis is "the motherboard has gone, replace the lot." Sometimes that is genuinely true. Very often it is not. The difference between a simple firmware reflash and a full board replacement is the difference between a sensible bill and an eye-watering one.

The point is not that a firmware reflash always wins. It is that a dead laptop deserves a real diagnosis before anyone reaches for the most expensive answer. Where a fault does turn out to sit on the board itself, we replace the relevant part or the whole board, or advise the most cost-effective route; we do not carry out board-level or soldering repairs. Our honest take on this trade-off lives in our repair or replace guide, and if you want a sense of typical pricing before you commit, see our page on how much it costs to fix a laptop.

Common mistakes people make with a dead laptop

Over the years we have seen the same avoidable missteps cost people money and, occasionally, their data. A few worth flagging:

• Assuming "won't turn on" means "data is gone." In a no-power fault like this one, the storage drive is usually completely fine. The data was never at risk; the machine simply could not reach it. Once the laptop boots again, everything is there.
• Repeatedly forcing it on and off. Hammering the power button rarely helps and can occasionally make a marginal fault worse. One careful hard reset is worth more than fifty frustrated jabs.
• Buying random parts on a hunch. Ordering a replacement battery, charger or even a motherboard before the fault is diagnosed is a common and expensive gamble. Diagnose first, buy second.
• Opening it up without the right tools or knowledge. Modern laptops are tightly packed, and the firmware chip is small and easily damaged. Well-meaning DIY can turn a cheap repair into a dear one.
• Writing it off too soon. The biggest mistake of all. A machine that looks completely dead is, more often than people expect, a quick fix away from working perfectly.

If your laptop does still run but feels slow or unreliable rather than dead, the fixes are different again; our piece on why a laptop runs slow and our laptop care guide are the right places to start.

Why the HP EliteBook 840 G6 is worth repairing

It is also worth saying why this particular machine was so clearly worth saving. The EliteBook 840 series is a business-grade laptop, and that is not just marketing. These machines are built around an aluminium and magnesium chassis and are tested against military-style durability standards (the MIL-STD-810 testing regime), which covers things like shocks, vibration and temperature. They are designed for years of daily professional use, with long-term support, manageability features and security hardware like the Sure Start protection mentioned above baked in.

In practice, that means a well-kept EliteBook 840 G6 still has plenty of useful life in it. Throwing one away over a corrupted firmware chip would be like scrapping a reliable car because of a flat battery. For a business especially, keeping a known, trusted machine in service avoids the cost of a new device, the time lost setting it up, and the disruption of moving everything across. A quick firmware reflash put a dependable workhorse straight back on the desk where it belonged. If you run a business and keeping your fleet of machines running matters, our business computer support service is built around exactly that, and you can read more in our piece on how we help Manchester businesses.

The cheaper, greener fix

The easy assumption with a dead laptop is that the motherboard needs replacing, or that the machine is scrap. By diagnosing the real cause and reflashing the BIOS, we saved this business both an expensive motherboard and the cost of a new laptop, and kept a perfectly good machine in service, the sustainable approach we apply to every repair.

That greener angle is not an afterthought. Electronics carry a real environmental cost, which is part of why the UK regulates how electrical equipment is reused and recycled under the WEEE rules; GOV.UK's guidance on electrical waste sets out how sellers must support reuse and recycling and why separating this waste matters. Every laptop we bring back from the brink is one that does not become waste, and one less new machine that has to be manufactured. Repair is very often the genuinely responsible choice, which is also the spirit behind the wider right to repair movement we have written about.

Related reading: if your laptop runs but feels sluggish rather than dead, see why laptops run slow, and our guide on repair versus replace covers when a repair is worthwhile. We have also brought other EliteBooks back to life, including an HP EliteBook 840 G2 repair.

A quick word on your data

One worry we hear constantly with a dead laptop is "what about all my files?" With a no-power fault caused by corrupted firmware, your data sits safely on the storage drive the whole time; the machine simply could not get far enough to read it. Once the firmware is restored, everything is back exactly as you left it. That said, this kind of scare is a useful nudge: faults do happen, and a current backup is the single best insurance against any of them. Our guide on why backing up your data is critical is worth ten minutes of your time, and if a drive ever does fail rather than just refuse to boot, our data recovery service can help.

How Manchester PC can help

If your laptop will not turn on despite charging, do not assume it is dead. We diagnose no-power faults properly, from BIOS issues to power circuitry, and fix them at the cheapest effective level. Where a fault is traced to the board itself we replace the relevant part or the whole board, or advise the most cost-effective route; we do not carry out board-level or soldering repairs. We also offer fast collection for Manchester businesses, so a dead machine does not become days of lost work.

We cover Manchester and the surrounding areas with free local collection and return, fair pricing and honest advice, we will always tell you when a repair is not worth it rather than push one. For an HP laptop repair or any computer repair, get a free, no-obligation quote or call us on 0161 820 1992.