Go to File, Import and import the table that contains the new data

It will be given the same name as your original table but will have a 1 on
the end.
Set up an Append Query (having done this once, you can use the same append.
Append the data from the imported table to the archive one. Delete the
appended records from your original table.

A couple of things to note. You can't append to an  Autonumber primary key
field but if you decide to have a Number field in your archive table and
append an Autonuimber field to that, you may not be able to have it as a
primary key field because if you Compact your New Sales mdb after deleting
the data,  the Autonumber will reset and you will have duplicate values. One
way of preventing this, would be to enter a record into new
sales -anything - compact the new sales database, and then deleting your
dummy record.
You will need some way of ensuring that you don't append the same data more
than once.
Evi

I find your description confusing.
Which mdb has the table you want to update?
From which mdb do you want to do the update?
Are you updating existing records or adding new records or both?

In any case, you can link to multiple mdb files from your application mdb,
so really, it should just a matter of creating a link to the table you want
to update and running a query to perform the update.