I have sheets in seperate workbooks, both have the same two columns I am
looking to match (User and Date). Sheet1 is updated every week and used to
send data to sheet2. How do I check sheet2 for matches in these two columns
before adding data from sheet1? Also, If there are any matches how do I
delete/overwrite them so only the newest data is recorded?

Sheet1 Sheet 2

User Date User Date
1 1/2/2009 1
1/9/2009
2 1/2/2009 1
1/9/2009
1 1/9/2009 1
1/9/2009
4 1/2/2009 1
1/9/2009
5 12/26/2008