One of my family's laptops stopped working. It was working fine (according to third party reports - I don't use the laptop), and now suddenly it's not.

Powering on the laptop turns on the light on the power button, and the fan starts running (and continues to run until I turn it off or pull the plug), but the screen stays off. Nothing shows up on the screen, The screen's backlight doesn't even turn on. I've tried using an external monitor as well (via HDMI), but got nothing.

It just sits there, blank-screened, with the fan spinning and the power-light on. The power cable seems to be working fine...

Things I've already tried include:

1) Taking the laptop (mostly) apart and making sure (most) of the connections are still good, dusted it out.

2) Unplugging the power cable, and the battery, draining the power on the machine, then plugging them back in.

3) Running purely off of battery power, no cable. Running purely off of cable power, no battery.

4) Plugging in an external monitor incase the laptop screen was broken. No signal received (via HDMI - haven't tried VGA yet. Would the HDMI driver not be usable early in the booting process?).

My guess: Something in the BIOS boot process is failing - perhaps one of the hardware self-tests. No beeps, flashing lights, or on-screen text is notifying me of this though, so I don't have anything to go off of.

I've taken out the RAM and switched what slot it was in, and also tried re-seating it in the same slot, to make sure it had a good connection. Maybe the RAM stick itself failed? It doesn't fit in my desktop PC, so I haven't tested the stick of RAM itself.

The laptop isn't ancient, but it is kinda old. 5 years maybe. It was running smoothly, and was in good physical shape (not noticeably heavily worn). Seeing that it was functioning fine for what it was used for, I typically keep the family computers chugging along for as long as possible. I've done a few minor part replacements on it previously - replacing the built-in keyboard and replacing the flimsy internal cable running to the monitor (but any external monitor output shouldn't run through that, so I don't think that's the problem).

Maybe it's time to shoot it dead and get a new one, but it doesn't feel "dead" to me - it doesn't even feel "dying" - it seems like it was running fine (what little interactions I've had with it, maybe four or five times a month).

I'm just completely lost how to debug it if it's a BIOS issue. My knowledge in this area is non-existent. How can I troubleshoot it, if I'm not receiving any kind of output except the fan noise? Any hunches or troubleshooting tips you can give me?

It could be integrated GPU going the way of the dinosaurs. There isn't much you can do about that.

If its the BIOS and there isn't an easy way to install a newly downloaded one, you're out of luck too.

This sounds exactly like a problem that happened to my desktop. I tried everything and it turned out at the end to be the power supply.

Newer mother boards sometimes don't have speakers built in to beep( mine for example). Make sure there is actually a built in speaker on the mother board. Otherwise you need to buy this.

Two things come to mind:

1.) Some laptops need to be told to utilise the external monitor -- as an older model it might behoove to check if this is the case - usually [function + another key]

2.) The ram could be a source. Try moving it to a different slot (you may have already tried this when you dusted/checked connections)

Possible issues outside of what you have covered:

Backlight failure - could be as simple as the inverter which relatively inexpensive to repair up to the backlight which is conceivably a lot more in costs

Faulty motherboard.

Your bios issue will have reset to factory default when you powered down and discharged excess power after removing the battery. If the bios itself is faulty then around a hundred for a tech to replace/repair.

The reality is if you have to chase up techs to do a repair - give serious consideration to simply replacing it.

edit: and try the VGA output -- bios can be setup for hdmi as output but what the factory default settings on your system are I don't know.

Post the laptop mark "Acer", "HP"... it would help resolve issue a lot, also if its not secret its model.

Try if they didn't accidentally didn't switch the laptop display. Does the external monitor show "No signal" or is it just black?

Try if they didn't accidentally put brightness to 0, making display output black.

In case you didn't note that because i don't know your model i cant confirm if you need combination of keys or only 1 key press or more combined. Try pressing(FN key that is usually near CTRL Start button, and the other key is usually between 4 and 6 button it is written "Display" or a white square or anything representing square inside a square.

Also try pressing the Display button on its own without the function key.

Also it does not hurt to try to empty all capacitors and start it again, i have had issues like that... Never figured out what caused them.

Unplug power source, remove battery and press-hold power button for 15 sec. Then plug it back in and try starting it again.

My guess: Something in the BIOS boot process is failing - perhaps one of the hardware self-tests. No beeps, flashing lights, or on-screen text is notifying me of this though, so I don't have anything to go off of.

By this did you mean that when you press the power button, the laptop powers on, then turns off in matter of seconds then powers up and runs as it is supposed to?

If so, its normal.

I'm just completely lost how to debug it if it's a BIOS issue. My knowledge in this area is non-existent. How can I troubleshoot it, if I'm not receiving any kind of output except the fan noise? Any hunches or troubleshooting tips you can give me?

If you think bios is broken, just flash it to factory setting.

Maybe it's time to shoot it dead and get a new one, but it doesn't feel "dead" to me - it doesn't even feel "dying"

A computer is a complex piece of hardware, often falling apart slowing (single electronical elements get damaged and stopped working or stopped working under load). I encountered this effect (black screen, fans are running, harddisc are not spinning up) often, after my current video card stopped working in my main PC. Still the video card was ok and worked in an other PC, and using an other video card I got my PC still working. This way I needed to exchange my videocard 3 times in 2 years until I gave up and bought a new motherboard.

My guess was, that the motherboard got damaged and wasn't able to powerup with all the demanding hardware pieces plugged in (therefor you dont hear any warning peeps). Try to turn off as much as possible (hdd, memory, videocard per jumper?) to see, what could be the cause.

i've experienced this with desktops, generally was due to bad seated ram(one time it was actually an improperly seated cpu). it sounds like you've ran through alot of the troubleshooting steps though. the most i'd recommend is checking if any of your other laptops share a ram type with this pc, and try swapping between them. it could be any number of parts though to be honest, and with no beep codes, combined with most parts being soldered into the motherboard, it makes it very difficult to narrow down the exact point of failure.

@SteveDefact0, not sure if laptop motherboards even have an spot for an speaker to be plugged in.

Thanks for the help gents. The laptop is a HP Pavilion g-series (I think a G7, not sure). I did a bunch of googling of that model before bugging you gents, and people basically say the same thing: Power down, remove battery, discharge residual energy; as well as checking that the RAM is properly seated.

Here's what I've just tried today:

Took the motherboard entirely out of the laptop casing (sans harddrive, RAM, DVD drive, battery), plugged a TV into the motherboard via VGA, powered on the motherboard. Nothing but the fan spinning (and the "power on" indicator light). TV gives "No signal" message.

Plugged back in the stick of RAM, plugged in the laptop's built-in keyboard, powered on the motherboard, still plugged into TV via VGA. Nothing but the fan spinning, TV gives the typical "No signal" for 30 seconds or so before the TV powers itself off to save energy.

So, basically either the motherboard w/ integrated GPU, or the stick of RAM is faulty.

I just this week took apart another laptop because it died an unrelated death - but the other laptop is ancient (~2005) so unfortunately the RAM sticks don't fit the slots of the problem-machine.

I have one other functionally-good laptop that is a very close match in age and specs, and might have compatible RAM, so I'll try that tomorrow. If it fits and if it works, cool - then the RAM was the issue and I can order a new stick. Though at $50 for an equivalent stick of RAM, I'd rather just toss the $50 towards a new machine - 5 years is a decent lifespan for a laptop anyway. Still, at this point I'm very curious which piece is the defective one.

Still, at this point I'm very curious which piece is the defective one.