Interchanging data between two files

[Puttster]

I have two lists of names and addresses, with columns for Last Name, First Name, Street Address, Suburb, etc. and rows with the people's names.

There are about 1600 rows of information and 20 columns for each person.

I want to be able to update the data that is missing from one file and exists in the other (which does not have all of the data from the first file).

I can work out which names need to be updated by sorting the information in one list to show blank lines of information, but how can I make a block of cells with only the information I want to copy?

I have used "=IF(ISNA(MATCH($A2,$U$2:$U$2000,0)),"",$A2)" to sort which names in column A (the last names of the people whose addresses are missing) are in column U, which contains the data I need. I also created the same argument in the next column to match the first name with the last name. I can then Copy and Paste Special this information to sort it alphabetically (woo hoo, clever me).

I tried to create a nested IF statement in another column to compare Cell Ax with Column U (last names) and Cell Bx with Column V (first names), and to copy the contact details from Cell Wx if the first two arguments are true.

I must have the syntax wrong, or I'm going about this totally the wrong way, because I can only get Error:508 from this argument:

=IF(AND(ISNA(MATCH($A2,$U$2:$U$2000,0)),(ISNA(MATCH($B2,$V$2:$V$2000,0)),"",$W2))

I'm stuck. Can anyone help me out here?