title: How to Remove Duplicates from two Excel sheets
body: <p>The Problem - I have two excel sheets (in one workbook) with many hundreds of lines of data, let's say a company name (column a) and the company registration number (column b). </p>
  
  <p>Some lines appear on both sheets and I wish to delete the duplications on one of the sheets only, say Sheet 2. So I am thinking to mark the duplicates with an 'X' in Column C so I can sort them and mass delete.</p>
  
  <p>I'm trying to use a formula in column C that says if the 'company' number appearing in column b on sheet 2 appears in a cell range on Sheet 1, then mark the corresponding cell in column c on sheet 2 with an X. </p>
  
  <p>I can then sort sheet 2 and easily delete the duplications. I think the formula in the cells in column C on Sheet2 should look like.... =IF(Sheet1!B1:B1000=B1,"X"," ") ....but it's not working. </p>
  
  <p>Any suggestions please? I am not a programmer ;)</p>