I think one of the issues with computer literacy these days is that everything is a bit obscured and "too easy" - so you can end up knowing how to do something on one particular system, but don't really understand what's happening "behind the scenes" when you press this or that button. So if the interface has a complete makeover, or you need to use a different system one day, you're lost, rather than being able to say OK, I need to achieve X and looking for a button or menu option that sounds like it might be related to X.
If you can gain a bit of understanding about the underlying systems of IT it becomes a lot easier to navigate things, IME. It's not too hard to build that up from scratch, but it can be tricky to know where to start, and difficult to follow if you're not interested in something.
I would recommend just picking a really simple task - let's say, drawing a stick man in MS Paint, saving the document, retrieving it later, maybe printing it. Paint is very simple as programs go, and since the document is something silly (a stick man picture!) it really doesn't matter if you mess it up. It would give you a grounding in how programs in general work, the file system, looking for and identifying buttons, using menus and dialogue boxes.
Once you've got the basics down you can then play around with the different tools to see what happens - can you make your stick man change colour, change the background, give him a speech bubble with something to say inside, use copy and paste to make lots of stick men?
These skills are then transferable to other programs because most computer programs use the same kinds of features - buttons, menus, text boxes.