If you are able to view other Office documents as you stated in your comment then the problem is only with viewing Word files. Your OWA settings should be fine.
Now open your Central Admin > Application Management > Manage Services on Server and check if Word Viewing Service is created and running.
At your client side ensure to check the document title bar for "[Compatibility Mode]".
Go: File > Info, and then click Convert.
Save the document as Word Document (.docx) before uploading to a document library.