Hi afs24,
If your data if of the text variety, then this SQL should do what you need:
DELETE Tbl1.Enter_Field, Left([enter_field],2) AS left2
FROM Tbl1
WHERE (((Left([enter_field],2))="SP"));
To use this, create a new query in design view. Click on the little downward-pointing arrow on the button you click to switch between design and datasheet view, and selecing SQL. Then insert the above phrase.
All I did to do this, was create a new query in design view, insert a table with data like yours, and then wrote this expression where you would normally have the field name:
left2: Left([enter_field],2)
left2 is an arbitrary name for the column.
Then set the criteria in this field to "SP", or whatever you want to get.
Now select 'query' on the main toolbar, and change the query type to a delete table (you'll have to extend the window, most likely).
Now, when you're ready, click on the little exclamation point, or double click on the query's icon when the query is closed, and it will run, seleting the records for wich you specified criteria.
HTH,