Insert 1 cell  at the top of the column
Select the whole of the column  below the blank
Copy
Move to the cell to the right of the blank  column
Paste
Move to the next column to the right and type =MOD(ROW(),2)
Copy this formula all the way down


Then select the 3 columns and go
Data/Filter/Autofilter
Click the little arrow above the new column (which contains 1s and 0s)
Select 1 or zero (whichever is opposite the second data  row)
Select all the visible data, Right click, and select delete  row
Confirm
Remove the autofilter