I want a formula
Highlight every cell in Col A that matches one or more cells in Col B
Apply conditional formatting to the cells of your interest in Col A.
Conditional formatting can be found dirrenetly depending on which
MsOffice you use (2003 (Format menu) vs 2007-2010 (find somewhere on
the ribbon)).
The conditional formatting criteria would be a formula:
=COUNTIF($B$1:$B$57350,A1)
Bear in mind that this might be quite a slow process as for the file
there will be 3,000 calcs to make and each calc will need to search
57K rows.