Computer Won't Stay Off

When I shut down my PC, after it turns off (all the fans stop, mobo lights stop blinking, etc.), it will almost immediately turn back on and go through a perfectly normal boot, with absolutely no intervention from me.

Moreover, if I physically hold the power button on the front till it goes off, it will turn right back on once I let go.

The only way to make it stay off is to either unplug it completely from power or to flip the physical switch on the back of the power supply.

I’m not SUPER concerned (as I almost never turn off my PC unless I’m leaving for an extended period of time, and then I just unplug it anyway) about this, but it is pretty annoying when I’m getting ready to open it up and perform surgery.

My guess is that there’s a short in a wire somewhere, but I’ve opened the old girl up a couple of times since I started noticing this and didn’t see any obvious bits of metal or broken wires touching things they shouldn’t be touching. If there is somewhere in particular I should be looking, though, or another potential cause, I’d love to know :)

Has it always been this way or is this a recent thing? You may have a defective power wire on the case or defective pins on the board.

I’d try disconnecting the power wire coming from the case to the mobo. It’s usually labelled “power sw” or some such. Then, turn it on by shorting the power switch pins with a screwdriver. See if you can control on/off that way. If so, then you simply have to address the case power wire or button.

If you can’t locate the power wire, post your mobo make so someone can point you to it.

You may also want to call an exorcist, in case it’s possessed.

It’s “recent” insofar as it wasn’t the case when I put this PC together in August 2009, and I am fairly certain it wasn’t occurring when I moved to my apartment in October of that same year, as I don’t remember it turning on the second I plugged it in :)

Since then, the only times I’ve ever really turned it off are when I was going to open it up to start working on it, and the last few times I’ve done that, I’ve noticed the bug. So it’s hard to say exactly how recent it was and if it was tied directly to my hardware tinkering or if it arose “naturally.”

I do know the wire you’re talking about and should be able to find it again without a lot of difficulty (my cable management would make most of you cry though). When you say “short the power switch pins,” what exactly should I do? Just jab a flathead screwdriver into the same jack that the wire is normally plugged into, or are there two or more specific pins within that structure that I need to bridge in particular?

Power switch connectors on mobos are usually two pins, a live and a ground, that stand upright. It isn’t really a jack. The case power cable sits on top of these two pins.

Just use a screw driver to touch both pins at once. Note that power switch connectors usually are arranged with a ton of other connectors: case speaker, HD light, power light, etc. Make sure you find the right one.

I would guess it’s a short on the power switch connection to the motherboard also, but you might want to check your BIOS for an always on option too.

Gotchya on the pin-number. I may have been remembering one of the similar “jacks,” like the USB connectors on the mobo, but now that you describe it, I remember that little section of two-pin connectors and carefully arranging a gaggle of wires from the case there :)

I’ll pop it open tomorrow when there’s decent lighting in here and report back. Thanks for the advice!

Disconnect the Wake On LAN cable while you’re in there.

Have you updated BIOS recently?

There are a few options there where you set both the default action for your power button, and for restarting upon switch press. Since this is separate form what the OS does, it’s worth checking.

Your symptoms do sound like something more than that, but it’s worth a check to see if things are set correctly.

I had a similar problem. IIRC, the cause was my UPS was constantly transmitting data via USB, which triggered my PC’s wake-up. I had to either disconnect the UPS USB cable (thus losing the ability to trigger an auto-shutdown when I lost power) or disable Windows’s wake-on-USB feature; I chose the latter. Now I just use the power button to wake it up instead.

I had this problem a few months ago - turned out my graphics card was not inserted fully. Strangely, it didn’t affect graphics or graphics performance but I did notice the card’s fan going from dead silent to full blast randomly.

I noticed it being raised maybe a millimeter and a half or so from the bay and when I’d push it in it would go all full blast fan on me. Anyway, had to re-insert it (almost broke the damn card since I always had trouble making it fit all proper like, but this time I used a hammer - seriously) and since then it stays off.

Johnny Five is alive! Hello, Moles!

A hammer??!!! I don’t think I’d ever consider a hammer to get a card into a slot. If it’s that hard to put in, I’d assume that the card and the slot aren’t compatible in a round holes , square peg kind of way and continue to scratch my head.

Er, yeah, if you have to use a hammer to seat any sort of slotted component in your PC, something else is pretty wrong.

But a jackhammer is okay, right?

I cringed. Plus, when it comes time upgrade the card, how can that card be removed?

A hammer.
Why didn’t anybody suggest that solution when I recently had trouble fitting a graphic card?

Well, poking around more has revealed a few things:

There’s no obvious obstructions or bits causing a short on the pins, and the actual connector basically looks like it’s on there okay. . .

. . . unfortunately, testing it didn’t go so hot as I then discovered that the only way I was ever, ever getting it off the mobo (much less touching the pins with a screwdriver or reconnecting the wire) was by removing about half the components in my PC. Looks like downsizing from an Antec 900 to a 300 wasn’t such a good move for my cable organization :(

Anyways, when I do end up moving back to the 900 (I “lost” it for several months while UPS held it while deciding that kicking multiple large holes into my box that was stuffed to the gills with various sorts of super-safe insulating materials didn’t make them responsible for the massive damage to the computer within), I’ll test this more thoroughly. Till then, guess I just gotta keep giving that powerswitch on the back the good ol’ reacharound to turn this sucker off =/

Lol, just read some of the responses to my “hammer”.

First off, I didn’t just start whacking away at the video card. I wrapped a thick padded cloth over the top edge of the card and then I just gave it a couple of light, careful taps.

The card was about 98% in… there was always just some resistance that wouldn’t allow it to go in all the way and I couldn’t figure it out. Didn’t bug me since the card always worked until a few months ago when the fans started going whack and then I had the power issue.

Anyway, not worried about a later upgrade - that PC is 7 years old and going in the garbage sometime soon which is why I was not reluctant to use the hammer!

And uh, no I don’t suggest a hammer as part of your PC care tool box, lol.

Did he ever confirm that he checked the BIOS?

Finally! Someone other than me who remembers Electric Dreams! The epitome of 80’s B-level comedies.