It may not help in your specific instance, but...
byte[] to string:
byte[] bytes = ...
string s = System.Text.Encoding.ASCII.GetString(bytes);
The reason it may not help is that a Word file is not just text - there is a lot (and I do mean a lot) of extra information which describes how to display the text, among other stuff. What you get as a string will very probably not be directly displayable as text.