alarm sounds at midnight

Even when switched off ( unless the power cord is pulled out) my computer sounds an alarm at midnight , and again ten minutes later . It wakes up my wife - even though the computer is in a different part of the house with closed doors . ( Not me, but then I am a bit deaf).
The info in the help screen in XP home tells me to go to Power Options in Control Panel and then click on the alarm tab - but I can't find the alarm tab ( and this may be the wrong answer anyway). Any ideas which might save my marriage, or save me being sent to live in the dog kennel at the bottom of the garden with my computer ?

 

Where/when do you get the help screen?

I'm not aware of any alarm feature within the OS and didn't see an alarm tab in the power section either. It is possible that some 3rd party app could add the alarm and the extra tab I suppose.

 

I think the alarm tab is put there if you have a UPS. I have one and I have the alarm tab. The settings on it are all related to the UPS. I never did install any software for it after I installed XP. I'd guess XP has it's own drivers for it and it was put there during the installation. It shouldn't have anything to do with any alarm going off once you've shutdown windows. I'd have a look in the bios setup and see if there's anything in there that can be causing it. Maybe something related to the wake on lan setting or some such thing.

 

If the machine is literally off, is it possible the noise is coming from a UPS directly? My UPS will squeal like a pig every time lightning strikes, or a goof runs into a telephone pole. If you unplug the ups from the wall, does it make the squeal you hear at midnight?

 

I was sort of thinking the same thing except for this line in GeoffH's post.

With my UPS and others I'm familiar with, when you unplug the cord it'll start squawking at you almost immediately as it should (even with windows shutdown). After all, the power has been cut to it and it's only responding as it should. If GeoffH unplugs it and it quits making the noise, it would suggest to me that it's not a UPS that's being unplugged. Maybe they act different when the battery is bad though. I really don't know what they do then as I've never had one go bad.

 

In my BIOS, under Power Management, are settings for RTC Alarm (Real Time Clock) and all of mine are disabled. Apparently, this wakes a sleeping system from a remote request. Try shutting RTC off in BIOS for peace and quiet, and good luck staying out of the doghouse!

Johanna