Quiet?

This afternoon, I came in to the living room to play with Justin and Ashleigh. When I sat down on the couch, I noticed something different. The room seemed "quiet"...

I immediatly checked the fish tank to make sure the pump was still going. It's not that loud when it is on, but you can notice when it's humming. It seemed to be fine.

Then I came over to the computer...AHA! It was OFF! We "log out" each time we walk away from it, but while I was out of the room, Ashleigh must have pressed enough buttons to shut the thing down! Again, it's not a LOUD sound when it is on, just a sound we are quite used to.