When you’re selecting individual cells, you can use the arrow keys to move the selection around.
If you hold down the shift key, and then press an arrow key. You can extend this selection in any direction without using the mouse.
To select an entire column, press control-spacebar. Once you have the column selected, you can press shift and extend the selection to the right or left using the arrow keys.
To select an entire row, press shift-spacebar. As with columns, you can then hold the shift key down and use the arrow keys to extend the selection.
When you are inside a group of cells, control-A will select the entire group. If you type control-A again, you’ll select the entire worksheet.
If you want to select a row inside a group of cells, select the first cell, then hold down the shift key and the control key and press the arrow key. Excel will extend the selection to the first empty cell.
This will work for columns as well. Select a cell, then, holding down both the control key and the shift key, press the arrow key in the direction you want to select.
Keeping the shift and control key held down, you can type an arrow key to select the remaining cells in the group.