It is Auto-correcting my capitalization

I have a Microsoft Wireless Comfort Keyboard 1.0A Model 1027. Somehow it is Auto-correcting my capitalization in Word, my Browser, and Windows Explorer. In Word: Office Button>Word Options>Proofing>Auto Correct Options...>"Auto Correct" tab, none of the auto correct boxes for Capitalization mistakes are checked.
If I try to type something like USDA, it might come out as USDa. I believe I remember that it can also come out as Usda, or USda, but am not 100% sure. It seems to be somewhat random and intermittent; it sometimes will do what I want.
After a while, this behavior is incredibly annoying. I very much want to see exactly what I am typing and don't want to be second guessed about it.
How can this be corrected?
Thank-you for your time.