Yes, you can create a simple Windows Forms application that would let you work as a Word editor. Since you're not to use the Office API and you are just going to create a new application that would let you edit the text and other such tasks, you might be interested in RichTextBox object in Windows Form, because it would let you include some formatting to the text like Word too.
http://msdn.microsoft.com/en-us/library/system.windows.forms.richtextbox%28v=vs.110%29.aspx[
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If you go to above attached document, you will find some example codes that would get you familiar with this object too.