Say for example that when you get home from work, you put your wallet in a drawer and then write down on a piece of paper instructions how to find it. The following day, you throw away the piece of paper and forget where your wallet is. It's still technically there, but you can't find it; the wallet has been deleted.

Eventually you get a new wallet and need to put it somewhere. You open the drawer and see your old wallet there. It's irrelevant now, so you throw it out, put the new wallet in, and write down on a piece of paper instructions how to find it.

The wallet is a computer file.

EDIT: At least, this is the olde way of doing things. Looks like the youths have gone and made things all different and frightening.