If you want to select a whole spreadsheet in Excel, you can use the familiar Control-A shortcut (which also works in many other apps). For a more mouse-centric alternative, click in the empty box next to Row A and column 1 (with a shaded triangle on it).
The keyboard version has one difference to the mouse approach: if you type Control-A whilst inside a table, that will select the table rather than the entire spreadsheet. Both options can be useful. (If you want to select all of a spreadsheet that includes tables using the keyboard, move to a cell which isn't in the table before typing Control-A.)
For more Excel shortcuts, check out the six most useful options we've discovered and the very handy use of the Control key to move around blocks of data.
[via Project Woman]