Are you hitting a hard return at the end of every line? This sets the internal flag to capitalize the beginning of the next line. Instead, just type and let the words wrap as they will.
Another option is to use a "soft" return. A soft return is shift-enter. It tells the computer to add a return, but to treat what follows as if it were still on the line above.
Of course you can always edit out the "help." When MS capitalizes, you can also go back and edit out the capitalization, but only after you've typed at least one letter after the errant capitalization. For instance:
You wanted
cigar
it typed
Cigar
so type
{enter}
ci [but Ci will show up]
{left arrow} [to get in front of the capital C]
{backspace} [to remove the capital C]
c [to put in a lower case c]
{right arrow] [to get back in front of the i]
and then "gar" to finish the word.
