iMac awakes at odd hours...help?

I have the 27" iMac. Using the settings under "energy saver", I set it to not awake or sleep at any time. Last night at 5am, the computer woke with the load BUMMMM!! and the bright white screen. Have to admit, it scared me have to death. This is the 3rd time it's done this in the last week and a half.

Any help as far as some settings I'm missing?

We're on a wireless network and the computer is shut down every night.

All help would be greatly appreciated. Thanks!

-Brent

When you say shutdown do you mean powered off?

I have a bluetooth keyboard and mouse attached to mine. When mine is a sleep, some times it wakes up in the middle of the night all by itself. I am assume its the keyboard or mouse loosing connections or a strong bluetooth signal.

Hmm. I meant when I powered it off. Mine makes no noise when it wakes up from sleep, only on start. I also have the wireless keyboard and mouse. I make sure I power the mouse off but I don't think I've shut the keyboard off before. I'll try that and see what happens. Thanks!

-Brent

I let my iMac sleep automatically after a couple hours of inactivity and when I'm heading to bed at night, I just hit the power button to put it sleep immediately. I haven't seen it wake up by itself until I come back the next day and hit the keyboard or mouse.

If you are powering if off, you SHOULD hear the Mac sound when it starts up, that means you'ave actually powered it off. If it starts up without the noise, it's just going to sleep not powering off..

Regards