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?