How would i know

Sometimes i wonder, if there stuff that you will know naturally without someone telling you? I mean you would not have known who are you relatives if your parents never tell you right or even who your parents are. Oops... well that is a bit extreme, but well sometimes how you know exactly what is going on?

If i'm a computer idiot, with so many software i will not even know that Windows is the OS while others are just software. Probably to me, i will think all programs are equally important though i don't use some of them and just neglect them, but in the end i will still not know which programs i cannot delete to free up more space.