Changing Upper Case To Lower Case

[AndiFlatland]

A few years ago, i had a friend who seemed to be able to do anything on a computer, and could answer any question. Unfortunately we are no longer in touch.
I will swear that he showed me a simple trick, which I've never been able to use since.
Often, when I type a lot of text into the screen, I accidentally hit the caps lock, and end up with a whole line or paragraph in capitals. It's absolutely infuriating to realise that I have to type the whole lot again.
I'm certain that my friend showed me how to simply change the caps to lower case without having to do it the long way - but I can't find how he did that. I've just asked at my local computer shop, and they say there is no way.
Does anybody know how to do that without wasting 10 minutes or half an hour laboriously tying it all in again?

[fiction-factory]

shift F3 or F2?

[Fitzer]

If you’re doing it in Word or Outlook there is a format text option to change case

[fiction-factory]

Works in Word anyway. Highlight then shift F2 or F3

[Peter Pedant]

if you are doing machine code
you AND it with FF
that is because upper and lower case ASCII differ by FF (*)
or amother number
but anyway you get the idea

a is 101 and A is 301
kind of