Sequential numbering in Access 2007

I am having a problem doing something in Access 2007
that I was always able to do in Access 2003. Let me give
you an example. A simple table with three columns, one
is the autonumbered column for each record, the second
is a product name and the third we will call serial number.
Let's say I have 100 records in that table. Nothing is
recorded in the serial number field. Then I go to make a
simple query. I select all records in that table. In the
query under the serial number coumn, I type 1 in first
record, 2 in the second record and 3 in the third record,
and from that point on Access automatically adds the
sequential number as I go down through the entire list fo
records. And the number could be any number, for instance,
1238578, but as long as I start the numbering, Access
takes over and understands that I want all records
numbered sequentially.

Now in 2007 it does not do that. Am I missing
something? Thanks.