Another option is to concatenate your zero with the cell entry. In a helper column inserted next to your column of numbers, enter this:

="0"&A1 (where A1 is the first cell in your column of numbers-adjust as needed. This will return a text entry that begins with zero)

Copy this down as far as needed. You can then copy this entire new row and paste Special>values over top of the original data and delete the inserted (helper) column.

Good Luck.