If the font is a PostScript font, make sure that PostScript fonts are available. On the taskbar, click Start, Settings, Control Panel (or, in Windows XP, Start, Control Panel). Double-click the Fonts folder. Choose Tools, Folder Options, TrueType, and make sure that the Show Only TrueType Fonts in the Programs on My Computer check box is cleared.
If you open a document that calls for fonts you don't have, Word substitutes other fonts. You can control which fonts are substituted by choosing Tools, Options, Compatibility and clicking Font Substitution. Word lists the fonts it is currently substituting and lets you choose different ones.
Check the Format, Paragraph dialog box to see whether you've set Line Spacing with an Exactly setting that is too small for the font size you're using.
Did you add or remove tab stops in ways that affected the tabs you placed in your document? Are stray tab stops still in your document that you thought you deleted? One way to find out is to display the tabs in your document by clicking the Show/Hide Paragraph Marks button on the Standard toolbar, pressing Shift+F1, and then clicking on a tab that is behaving oddly. Word's Format, Reveal Formatting task pane will display complete information about your current paragraph and tab formatting.
For Word to mark formatting inconsistencies, you must check the Mark Formatting Inconsistencies check box in the Edit tab of the Tools, Options dialog box. This check box is available only if you first check the Keep Track of Formatting check box immediately above it.