Change the paragraph After spacing from 10 to 0 points, and set Line
spacing: to Single, and make this your default.
In the Home tab, click the Paragraph launcher (lower right corner of the
Paragraph section). In the indents and spacing tab, look under Spacing to
make the changes. If you want this to be your new default when using that
template, click the Default button.
Or... change the style set to Word 2003. In the Home tab, click the Change
Styles dropdown, Style Set, Word 2003. Then choose Change Styles - Default.
Note that you can't do this for certain templates.