Well, can you see/edit existing records in the form, or does is ALWAYS go to
a new record?

If it always goes to a new records, then:
     You accident set the forms data enter property = yes...that what this
feature is supposed to do).

If you can see existing records, and can't add new ones, then:
       you likely set the forms allow additions = no

If you can see existing records, and can't edit them, then:
   Either your query is not a updateable query, or you set allows edits =
no.

What happens if you open up the query (the form is based on) , and try
editing data then? Can you add, can you edit? Does it display records?

     So, check the query the form based on...and see if it is editable, and
how it works....

the above is just a short list of things I would look at, but you not really
told us what you tried so far....