Access 2010 Update Query from text box parameters in a form

I am creating a golf club database as part of my studies, I had a few issues previously which were resolved on here, thanks.

But now I have another drama, I have an update query "Category_Update" which updates information into a table "tblWinners". There are 6 possible entries. M - J, M - A, M - S, F - J, F - A, F - S, where M is male, F is female, J is junior, A is adult and S being senior.

I have a macro which deletes the current entries in the "tblWinners" table and a form which uses text boxes to update the table using the query. Prior to adding the macro, if an entry matching the data I try to input is present (e.g. Gender:M and Category: A already in the table) it will attempt to run the query, but fail because "Gender" and "Category" are primary keys in the "tblWinners" table. But if the data I input does not match an existing entry the query will fail, not even attempting (as in 'You are about to append 0 row(s).' as opposed to 'You are about to append 1 row(s).' and then failing due the the primary key issue.

Previously in my study i read that you need an entry to append to, but with the deletion macro there is nothing to append to and so it fails.

Any help would be greatly appreciated.

Thanks,
Mark