Keys for moving around on a datasheet

To move	Press
To a cell	An arrow key
To the beginning of a row	HOME
To the first data cell (A1)	CTRL+HOME
To the end of a row (last occupied column)	END
To the lowest-right cell that contains data	CTRL+END
Down one window	PAGE DOWN
Up one window	PAGE UP
Right one window	ALT+PAGE DOWN
Left one window	ALT+PAGE UP
Up or down to the edge of the current data region	CTRL+UP ARROW or CTRL+DOWN ARROW
Left or right to the edge of the current data region	CTRL+LEFT ARROW or CTRL+RIGHT ARROW