In Word there is a feature that will mark all spaces and indents with marks or periods so you can visibly see how many spaces you have in a given sentence.
This feature can be turned on or off by clicking this button on your toolbar:
If you cannot see the formatting symbol you can turn the feature on or off by going to Tools > Options and selecting the View tab. You will see a section called Formatting Marks. Inside that section, check the box that says All. This will turn the feature on or off.
The default keyboard shortcut for enabling/disabling formatting marks is:
CTRL + *
CTRL + SHIFT + 8
Applies to Microsoft Word 2003.