How do you highlight a series of columns or rows using only the keyboard?

Ctrl + Space bar for entire column selection whereas

Shift + Space bar for entire row selection

To select columns: Ctrl + Space

To select Rows:Shift + Space

You could also use the following:

Ctrl + Shift then arrow keys depending on the direction of the data you intend to highlight.

Using this, you can reduce selection to the data you really intend to use and avoid highlighting the whole column or row.

Give it a try. :)