1. On the menu bar, click the button that looks like ¶. This will turn on hidden formatting characters. The ¶'s that appear show the ends of each paragraph. If there are extras between your lines, you can do a mass delete them this way:
2. Press CTRL/H to bring up the Find and Replace dialog box.
3. In the Find what, put ^p^p
This represents two adjacent paragraph marks.
4. In the Replace With, put a single ^p
5. Click the Replace All button.
6. Click the ¶ button again to turn off the hidden characters.
Hope that helps.