Have you ever inadvertently left Caps Lock on in either Word or PowerPoint, and have a length of text that has upper-case letters instead of lower-case ones and vice-versa?
If you are using Office 2007, Office 2010 or Microsoft Office 2013, then on the Home tab, in the Font group, you will see a button that has Aa on it; select the text which is causing problems, then click on the drop-down next to the Aa button and select the bottom option, which says tOGGLE cASE. Your text will then be transformed so that it is looking how you wanted it to.
If you are using an older version of Microsoft Office, select the text which is causing problems, click Format on the menu bar, then click Change Case. Select tOGGLE cASE, then click OK.