Highlight a column in the data and open the Go To window.  

  You can also use the Ctrl + G keyboard shortcut to access the Go To window.   Now only the blank cells in the column you highlighted will be selected.  

Delete these rows.  

  A similar trick will work for blank columns, just select Entire Column instead of Entire Row.   Voila! You just saved yourself a tonne of tedious work. Go take a 15 minute break and relax, you’ve earned it.