Terminology - a new record is one that hasn't been finished yet. In fact, it may not even have been started. You append new records; you update existing ones. You really can't update a new record. If by that you mean one that you've just created, then it's not a new record - it has the same "newness" as any other record. It might be distinguishable based on a create date/time, or many developers might rely on the greatest autonumber id to tell then which is the latest record.
So if this isn't what you're needing, then the reason is because of my misunderstanding of the terms you used...
You prevent updating of all existing records by providing criteria in the query that will restrict the records, and if possible, you join the two tables on a common field where at least one of them is unique. Since I can't see the tables, nor did you specify what the 4 fields are in the 2nd query, that's the best I can offer for now; except to say, experiment on table copies.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.