There is a bunch of ways you can handle this. One way is to query the database for the anem that you have. If it finds the name then don't do the update, if it doesn't find it then do the update. It is a simple if statement.
So here is some code for you:
dim sql, rs, update, searchname
searchname = whatever
sql = "select name from tablename where names = '" & searchname & "'"
set rs = conn.execute(sql)
If rs.EOF then
update = true
else
update = false
end if
If update = true then
sql = "INSERT INTO tablename(name) VALUES ('" & searchname & "')
conn.execute(sql)
end if
Oh you have to set your ODBC connection before this set of code. searchname is the name of the user that you are searching for.
Enjoy!