4. The Default Font Will Not Die
You don't like Word's out-of-the-box default font--it may be 11-point Calibri--so you change it. The next time you start a new document, it's 11-point Calibri. So you change it again. The next time you...well, you get the idea.
The trick is knowing where to change the font once and for all. Make the change in the Normal template, and it will stick.
Start a new document using the Normal template. If you don't know what I'm talking about, don't worry about it. Unless you know enough to do otherwise intentionally, your new documents are already using the Normal template.
On the Home tab, in the Styles section, right-click the Normal box and select Modify. Change the font in this dialog box, then click New documents based on this template before clicking OK.
If you use other templates besides Normal, you may have to change the default font in those templates, as well.
5. You Need to Reformat These Paragraphs But Not Those
It's a long document, broken up with subheadings. Then orders come down from on high: The subheadings, and only the subheadings, need to be in a different font.
For instance, you created the entire document in 12-point Bookman Old Style. To make the subheadings stand out, they're also bold and underlined. Your boss says they must be in 14-point bolded Arial.
You could go through the entire document and change them manually, but that's a real pain. And if you're told to change them again, it's a double pain.
If you used styles wisely when you created the document--for instance, assigning the Heading 2 style to the subheadings and the Normal style to everything else--you've got it covered. The job is easy:
Go to one of the subheadings--it doesn't matter which one. Select the entire paragraph, and change the formatting in whatever way you wish (or your boss wishes). Then right-click the paragraph, select Styles, then Update style name to Match Selection. For instance, if your subheadings use the Heading 2 style, you'd select Styles, then Update Heading 2 to Match Selection.
But if you didn't use styles to begin with, things will be more difficult. (And you'll probably use styles from now on.) You need to replace the formatting that currently defines subheadings with a style. You can do this with Find and Replace.
With the document up, press CTRL-h for the Find and Replace dialog box. Leave both the 'Find what' and 'Replace with' fields blank. If there's a More button in the lower left corner, click it.
Click the Format pull-down menu button. Select the options for the formatting that currently distinguish the headers. For instance, with our bold-and-underlined example, select Format, Font. For Font style, select Bold. For the Underline style, select the appropriate option.
With the cursor in the 'Replace with' field, click Format, then Style. Select the appropriate style, such as Heading 2.
Click Replace All.
Now that your subheaders have their own unique style, you can use the instructions described above to change them--and only them.
When you're processing words, you shouldn't have to worry about things like formatting and protecting your files. You should be free to concentrate on the really difficult parts of the job, like coming up with a good closing paragraph.