Computer starting all by itself...

[slicendice]

Hi
My PC is about 5 years old or so and has been a pretty dependable work horse. Over the last few months though, it's been prone to starting up all on its own. There doesn't seem to by any rhyme or reason as to why it's doing this but it does seem to be getting worse.
Usually it would happen within a time frame of around an hour after I'd shut it down - so I'd power down and then some time between a few minutes and an hour or so later, it would restart. However just recently it's got so bad that as soon as I power it off, it starts up again immediately. I have to stand there, hand on power cable to physically pull the power out the moment it's finished shutting down in order to stop it starting itself up again!

It's connected to a broadband router via LAN (RJ45) but I've been through the BIOS with a fine toothcomb and there are no "Wake on LAN" type settings in there anywhere. I recently replaced the PSU as well (the previous one died) but the problem is still happening.

I've got up to date anti-virus and spyware software and neither report any problems.

Does anyone have any idea why this might be happening and how I might be able to stop it?

Thanks very much

 

[slicendice]

Sorry, should have said...it's running Windows XP SP3

 

[Sympology]

Could be a faulty power switch shorting out. If possibel on your pc try swapping the Power and reset switches over (not always an option).

if you cant swap, does it power up as soon as you replace the power? If so, disconnect the power switch altogether and see if it still happens

Most people spend their time on the "urgent" rather than on the "important."

 

[BadBigBen]

other BIOS settings to check:

WakeOnRing or Power on by Ring, and WakeOnPME or PME event WakeUp...

also check to see if the system is set to wake on Keyboard, manual should have a section on this... could try an USB Keyboard if it has PS/2 type, and vice versa, or even another Keyboard altogether...

I have also seen PC's start up irregular due to DUST build up (wool mice), static discharge, and pests (roaches for example)...

Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

How to ask a question, when posting them to a professional forum.

 

[airbourne]

Could also be a faulty motherboard not caused by any external problem. Check to see if your capacitors are normal (no buldging or leaking).

(also as previously suggested): I'd remove the power switch, check for dust buildup anywhere on the motherboard, and probably setup a mouse/bug trap just outside the PC.

I had a mouse try to make a nest in a PC once. He was getting into the case because I did not put on the PCI slot covers back on after removing cards. I only discovered him after he was electrocuted trying to lick or chew on the PC speaker. Which was hidden and let me tell you it was tons of fun playing "find where the smell of rotting rodent was coming from".

 

[wahnula]

I have had the exact same problem with my relatively-new desktop. The way I make sure it stays OFF is to turn the PSU I/O switch OFF when I shut down the PC. It also wakes on a mouse wiggle but even with the mouse docked in its charger it still happens.

I think it's a minor MB fault, it does not bother me so long as I can control it with the PSU switch. If your PSU does not have one, just pull the plug from the PSU. It's a minor annoyance...

Tony

Users helping Users...

 

[gbaughma]

Could be a WOL setting.....



Just my 2¢

"What the captain doesn't realize is that we've secretly replaced his Dilithium Crystals with new Folger's Crystals."

--Greg

http://parallel.tzo.com

 

[slicendice]

Thanks for the input everyone. Just as a final test to see whether it was in any way LAN related, I unplugged the network cable last night, then shut it down....and lo and behold, it started right back up again!

So, as suggested above, I'd imagine that it's either the power switch or the mother board. I'll see if I can have a fiddle with the power switch...and check for dead rodents while I'm at it!

 

[gbaughma]

You could try turning it on, then unplugging the power header from the mobo.

That would tell you if you have a dodgy switch or not.



Just my 2¢

"What the captain doesn't realize is that we've secretly replaced his Dilithium Crystals with new Folger's Crystals."

--Greg

http://parallel.tzo.com

 

[wahnula]

Mine followed the MB when I changed cases. I think it's just a minor annoyance, not everything is worth getting updet about not being able to fix. It's well below my tolerance level for annoyances. I shut it down...if it turns on, it turns on. I have tried disconnecting the LAN, disconnecting the modem, disconnecting all USB, etc. It still does it, so I don't sweat it.

slicendice, you could try that...turn it off then disconnect EVERYTHING. If it still starts on its own, welcome to the club brother.

PCs are like people...none are perfect. And some are worth keeping even if ya can't fix 'em.

Tony

Users helping Users...

 

[gbaughma]

I just leave my PC on. lol



Just my 2¢

"What the captain doesn't realize is that we've secretly replaced his Dilithium Crystals with new Folger's Crystals."

--Greg

http://parallel.tzo.com

 

[BadBigBen]

gbaughma - No Irish then, eh?


slicendice - Before we are heading more into the hardware troubleshooting, there is a setting in XP which will let the PC restart upon encountering an error (BSOD), this might be the cause of the restarts when shutting down... and if that is the case, then the displayed BSOD will lead us to isolating the problem...

Disabling the “restart on system failure” feature may permit the exact cause to be isolated: Right-click on My Computer, click Properties, click the Advanced tab. Under “Startup & Recovery,” click Settings. Under “System Failure,” uncheck the box in front of “Automatically restart.”

source: SHUTDOWN & RESTART TROUBLESHOOTING




Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

How to ask a question, when posting them to a professional forum.

 

[wahnula]

Update...even though I'm not the OP I have (had) the same problem. Yesterday, the PC stayed shut down...and would not power up. Quick replacement with an alternate PSU showed it to be the faulty component. Another example of the PSU being the culprit in mysterious hardware issues.

I'll have to replace it, check operation for a few days, and will report back if it solved my similar problem.

Tony

Users helping Users...

 

[wahnula]

YUP...it was the PSU. If you have a spare try swapping it out. My mysterious power-ups are now gone.

Tony

Users helping Users...