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PC starts itself

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9 replies

by daz'n'ash Jul 8, 2003 last reply Jul 9, 2003

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Here is a very nysterious problem. I have a client who has a computer running Windows 2000 Pro with SP3. This PC is not very old at all, perhaps 2 years at the most. It runs very well without any conflicts at all, has plenty of ram, free hard drive space etc.
The problem:
After proper shut down of the computer, it will restart itself 30 to 60 minutes later with no user interaction at all.

Any suggestions?

9 replies

by thechas Jul 8, 2003

3 options:

Power switch: Since the ATX power switch is a simple momentary contact push button switch, they can fail and complete the circuit on their own.

Power Supply: If the power supply control circuit starts to fail, it can switch on the system by itself.
Remember, an ATX supply is on ALL the time. It switches to full on when instructed to do so by the motherboard.

Motherboard itself: Either too much current draw on the 5 volt standby line, a failure in the power control circuit, or a wake-on event is happening.

Start by entering BIOS setup and disabling ALL wake-on events in power management.

After power up, disconnect the cable for the power switch. then shut down and see if the system stays off.
You can use an ohm-meter to check how sensitive the power switch is to operate, or if it has a resistance of less than 1 Megohm when not pressed.

That then leave the power supply or the motherboard. Swap in a different power supply and see if that fixes things.

Chas

by daz'n'ash Jul 9, 2003

Hi Chas,
thanks again for your insightful ideas. I should have thought ot the wake on lan, wake on modem features in the BIOS. Anyway, I disabled them and the problem did not recur.

by 1stladytech Jul 9, 2003

Chas has good answers, but also check and see if Wake On Lan or Wake on Modem is enabled. I have seen several systems that have virus, trojan or spyware that will "wake" the system up to report or send out payload. Do a full virus check (I prefer Norton AntiVirus) and a spyware check with either Ad Aware or SpyBot's Search and Destroy. Both are available free for download at www.downloads.com or other places on the web.

Good luck

Vickie

by daz'n'ash Jul 9, 2003

Indeed you are correct about the wake on LAN. As for viruses, the system checks clean. It has just had an upgrade to Win2K Pro anyway.

by justanadmin Jul 9, 2003

Could also be a Wake-on-LAN feature if the system has a network card that is used. I've seen this happen on some LinkSys cards even when the card was not connected to the network.