How to Enable and/or Disable Automatic Capital Letters in Word : Links to Resources

For Word 2013
From the Microsoft Word Help
The article goes into more specific detail.

Click File, in the upper left hand corner of the document.
Click Options
Click Proofing
Click AutoCorrect Options.
http://office.microsoft.com/en-us/word-help/automatically-correct-capitalization-HA010354276.aspx

For earlier versions of Word:
Small Business Chronicle offers these steps.
The article linked below goes into greater detail.

On Word, find the Microsoft Office button.
"Word Options."
"Proofreading"
"AutoCorrect Options"
Take away checks from features you wish to disable.
You can create exceptions.
"OK."
Turning Off the Auto Capitalization in Word. By Laura Webster. Demand Media.
http://smallbusiness.chron.com/turning-off-auto-capitalization-word-38167.html