compaq laptop turns off during boot

[local]

i know i know. compaq had crummy laptops. this was a hand-me-down. heres the gist. after many problems with the computer that compaq wouldnt fix, they mailed it back to te previous owner with a new harddrive and the wrong mounting. the previous owner gave it to me when they gave up on it. i made my own mounting and rebuilt the computer to clean everything up. its been working pretty well for a couple weeks, running win2k. recently i was in the process of installing Debian on it. the phone rang and i put it down on the sofa, dropped from about 5 inches. thats the only thing i can think of that has happened. enough exposition. now the problem.

i power on and almost every time it lasts just shy of 10 seconds and then turns off, loudly. sometimes it does it on the Compaq screen. sometimes during mid-boot with the OS. it has only actually turned on all the way twice in the last couple days. once with BeOS r4.5.2 booting off a floppy, and once with Debian linux booting off the hard drive. every time ive tried to boot off an installation cd for an OS, it fails. at first i thought it might be somethign with the cd rom drive either being broken or contributing to the heat of the system, but it also fails when booting off the hard drive and when the cd rom is removed. i went through and one part at a time removed things from the system such as the pcmcia card, the cd rom, the battery, the hard drive, the sound card unit et alia until all that was left was the main board and the smaller board with the power button on it. still the same thing.

so, could my dropping it from 5 inches have made something loose, and if so what? i didnt see a place for any jumpers that may have come loose or anything like that. i also cant find a forum post anywhere that describs a similar problem. the warranty is void and i have no qualms about disassembly as you now know, so im willing to try just about anything.

i think ive given all the info. let me know if i missed something important.

-local

[Luigi]

maybe tha bateries just wore out
the same thing happened to my friends laptop once but it worked when it was running on ac power it ran very well till it was unplugged
well good luck  
and as far as i can tell he hasn't changed the batery since then and i dont think ur sofa was hard enough to cause  a good enough  jolt for anything to come out since laptop parts are screwed tight

[local]

i dont think it is the battery cuz it does it with just ac power or with battery and ac or with just battery. with the battery removed from the system it still happens.

more info: it also seems not to be a software problem not just because it happens w/o the harddrive in but also because sometimes it happens after bios has loaded and sometimes during.

any other thoughts? thanks so far.

-local

[local]

I think i have an idea. i just noticed the ac adapter i was using has an output of 20v. the computer needs 19v. it acts differently when i dont have it hooked up to the wall for a while. could that extra volt be causing the problem? im going to buy a new adapter at 19v but want to know if this might be it before i drop the cast.

-local