You don't need to get rid of the blank rows if you don't want/need to.

If the values you are comparing are in column A in each sheet, then this will indicate Match/No Match

=IF(A1="","",IF(COUNTIF(Data2!A:A,A1)>0,"Match","No Match")) and drag down.

It will work regardless of whether there are blank rows or not.

Regards, TMS