Lead selection how to switch off and how to use?

Hiya,

I have a screen where the first row is always selected:

Is there any way to switch this off i.e. I'd still like the user to select a row but I don't want the screen to start with a  row already selected.

Also once a user selects a row - how would I know which row the user has selected and then process only the details of that row?

Thanks for any help!