Open your query in design view.
Right Click on the line that joins the tables.
You should get a Join Type dialog. If you get a menu instead, close it and
try again. You have to have the mouse pointer just right.
The radio button #1 is probably selected "Show only records that match"
Select either #2 or #3 depending on which table is the One side of the
relationship.
Do this for all the joins.