When there's white-out all over the screen
So you know what shows to watch.
Because they know all the short cuts.
At the BP station. (thanks grandma)
XP Edit: Explanation(http://en.wikipedia.org/wiki/ChiRho)
None. Horses are not known to use operating systems nor computers for that matter.
A Dell.
There is correction fluid on screen.
The screen stays black when you check the time.