My mom brought home a Compaq Presario V4000 her boss was going to throw out, because it shuts off unexpectedly a few minutes after you turn it on. She's reported is also would BSOD a lot in the past. I've already ruled out a software cause, as it shut off while I was booting into safe-mode, and Speedfan has ruled out overheating. The battery seems to be fine, and even if it wasn't it does the same thing even when plugged in. Any idea what else could be causing this?

Faulty power supply comes to mind. It may need to be replaced.

Do you mean that it just abruptly turns off, or that it actually goes through the normal shut-down procedure?

It abruptly turns off. How could the power supply itself be the cause if it charges fine and the same thing happens even when running on batteries?

My sister got a freebie laptop with a similar situation. I'm not sure if it will be the same for you as you said it is not a overheating problem.

The fix for my sister's computer was the fan had popped off the CPU. Maybe it needs new thermal paste..? Or maybe if it has a fan for it, it is no longer working? Just throwing guesses out to look at. *shrug*

One of my old PowerBook's had the same issue, it turned out to be the PMU chip. It was faulty and would not sense power input randomly. So I had to replace the whole logic board ( or in my case, just got a new one, cause lol old powerbook )

So what would be the compaq equivalent of a PMU chip? Searches reveal only macs with this.

I had something like that happen to my computer. Though I think it was just that my laptop was overheating. Could that be it?

My old Satellite Pro would do this sometimes when the battery clip broke and was only being held in by duct tape. Are all your power sources getting good contact?

Maybe your computer is getting short-circuited, could you clean it out with compressed air?

I have thought about doing this, but it's a laptop, so I don't know how comfortable I'd be opening it up. Also, one of the screws is a torx, so I need to get the appropriate screwdriver first.

EDIT- works fine when plugged in with the battery removed. Worth noting also is that it doesn't keep time when shut off. Anyway this is a workable solution for the immediate future since my dad basically wants to use it as a desktop for digital photography. If he ever wants to use it on the road we can try buying a new battery for it.

not keeping time when turned off is the internal battery on the motherboard that keeps the time is dead..

if the battery causes problems you may have to open up the laptop, there might be a loose wire, or broken soldering needing fixed..if the battery is short circuiting causing the shutdown, it could damage the harddrive or motherboard, which would result in the needing of a brand-new laptop..

would be easier and cheaper to buy a new laptop instead of fixing the old one (attempting to self-fix may cause additional problems if you don't know what your doing)

How did you rule out overheating? The on-die temperature sensor could be malfunctioning, the thermal paste could be dried out? Although you say you used Speedfan - do you mean you used it to check the CPU temps? I'm leaning towards an internal power supply / regulation problem.

Yeah I used speedfan to check the CPU and HDD temps, and it shut off even when it wasn't hot to the touch. It's an older laptop, so I'm pretty sure the battery could be the culprit, but I'm wondering if I could check it with a multimeter to be sure?

Unlikely. Out of curiosity, have you tried running it without the battery, using just the power supply?

@KermM:

It'd be a good idea to check with a multimeter. I suspect it's the battery P:

Yes, that's what I said I'm doing now.