I've got a table with about 36,000 users which looks similar to this.

A B C D E
F G
User w1 w1 User w2
w2
data data
data data

user1 123 145 user1 534
1224
user2 123 145
user3 123 145 user3 534
1224
user4 123 145
user5 123 145 user5 534
1224

The table is similar to this, except every user has 5 cells of data.
Columns A-C is the users with their data from week1, Columns E-G is the
users with their data from week2. Each user has associated variables
that I wish to maintain. I would like to determine which users from
Column A do *not* appear in Column E and perhaps output that to another
file.

Can I do this in Excel or do I need a VB macro? Any suggestions?