You might want to try creating a new document that is 8x10 inches at 300 pixels/inch in PSE.
Open the image you are trying to print and drag it onto the new document.
Then select File > Print directly from PSE.
Under "Select print size" choose "Actual size."
Also check under Printer Preferences to make sure that you have borderless checked there. It might be set to create a border in either of those two places.