In Excel, suppose you have the data on Sheets 1 & 2, with FirstName LastName Address spanning columns A:C on each, and you want to find which 'members' on Sheet 2 also appear on Sheet 1. In that case, you could use a formula in D1 on Sheet 2 like:
=SUM(IF(A1&B1&C1=Sheet1!A:A&Sheet1!B:B&Sheet1!C:C, 1,0))
and copy down as far as needed. This will put a 1 on all rows for which a match is found, and 0 for all unmatched rows. If you then sort the data, by column D, all the 1s (members) will be grouped together, as will all the 0s (non-members).

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]

I used that formula but i got all zero's and no 1's .. I think it might only be checking 1 for 1, ie a1 against a1. I need it to check the entire list of names for any matches in the other list that may be in a different cell/row
ie:
sheet1
a1 -smith john 123 address

with
sheet2
e1 -smith john 123 address