Open control panel, select Large Icons under View by (top right). Select Folder Options, under the General tab dot the button for Single- click to open.... then apply then OK.
As for the tiles in the start screen, right click a tile not required, select 'unpin from start' at the bottom. To get a tile back to the start screen, right click a blank space then select 'all apps' at the bottom. In the 'all apps' screen right click a tile and select 'pin to start'.