There's just a gap where it used to be. I powered all the way down, and booted back up again, and it's still not there.

Checked the Control Panel -- it's checked. In fact, it's disabled, so I can't uncheck it even if I wanted to.

Where'd it go? I wish it would come back.

Also, the power button no longer brings up the "Lock Screen / Power Off / Etc" menu. It, in fact, now does nothing. Except power off if I hold it down for several seconds.

As far as I can remember I've done nothing to bring this upon myself. Solar flares?

OK, so I unplugged the AC adapter, and pulled the battery. After putting it all back together, everything is back to normal.

This scares me. Folks, I could use a hug right about now.