Computer switches off (or standby?) half an hour after switching on

hessodreamy

Not sure if this is a hardware or software issue, and kinda has me stumped. One of the office PCs has started the habit of daily switching itself off at about 9.30am. Except it's not off, because the power light is flashing orange. But it's not on, and not sleeping or hibernating, so I don't know what state it's in! But the screen's off and it doesn't respond to mouse or keyboard actions, or a short press of the power button (long press turns it off).

The pc is a dell optilex, running windows 7 ultimate. It's only recently started doing this, roughly coinciding with a change of location within the office.

There's nothing in the event logs that would indicate an intentional change of state, just the 'previous shut down was unexpected' message.

I've run windows security essentials scan and malwarebytes, both of which come up clean (and wouldn't a virus leave some activity in the event log?).

I've set the power options to not sleep or hibernate or turn off hard drives.

To try and replicate the issue at other times of day, I've altered the system clock to 9am, but the issue does not then arise at 9.30, system time.

Lastly, I did find a scheduled task for the google update at 9.22. I've disabled it and will see what happens on monday, but in light of the system clock points raised above I don't think this will be it.

I must say I'm stumped. Any suggestions as to causes or lines of further investigation?

Figment

Swap the monitor and cable (one at a time) with another machine to confirm whether the problem lies with the monitor, cable or PC.

I suspect the graphics card may be overheating. Does it shut down again 30 minutes after being restarted?

hessodreamy

Forgot to specify, the computer does not turn off after any 30 minutes. Just first thing in the morning. So, given normal working patterns it's hard to say if it's every 9.30, or after half any hour for the first switch on of the day!

But I'll try the monitor cable.

fwor

If you mean you've changed the system time in Windows, not in the BIOS, check in the BIOS that some practical joker hasn't messed about with the BIOS time-of-day power settings.

hessodreamy

Good thinking. I checked the bios and there's options to switch ON at a certain time (which was disabled), but no option to set a time to switch the computer off. Also the bios time is correct.

blindman

Look in the (online) manual for the Optiplex to see if the power light flashing

orange is one of the troubleshooting warning lights?

We have 300 Dell Optiplex 960's and about 10 kept powering down\rebooting for no apparent reason.

Power supplies were dodgy.

robmar0se

These intermittant probs can be difficult to suss as you've discovered. Dodgy components as aleady suggested above. Dodgy PSU's, a couple of other things that have caught me out in the past are (i) overheating, just moved next to a radiator (turned off in the morning?), or in direct sun? (ii) poor seal between the cpu and cooling fan?

hessodreamy

Fine ideas, all. But surely I'd see these problems, however intermittent, throughout the day, or even at random parts of the day. As it is it's just once a day, first thing in the morning. Could be a red herring throwing me off, but this aspect of the issue seems to preclude a lot of causes...

Figment

After checking whether the google update is the cause (and on the assumption it isn't), I suggest you don't switch it on until, say, 10am on Tuesday and see what happens

hessodreamy

Figment wrote: »

I suggest you don't switch it on until, say, 10am on Tuesday and see what happens

Yup, tried that. It runs fine. No problems after the normal switch off time.

Figment

Then it looks like your google update may be the culprit. Check the settings in Task Scheduler. Try changing the time GU runs.