If you search for a different ASCII code, it will not find the TABs that are causing you a problem. Maybe Word needs an option to make tabs/spaces/newlines visible and/or searchable? I haven’t used Word since, like, 1990, so I am not the one to tell you how the current version behaves.
But I can absolutely tell you that you should not be editing text files in Word, which is supposed to be a basic word processor; at any rate, not if it doesn’t work. Text editors are specifically designed to edit text files; you say you have already been doing this from within Notepad. If that is for some reason inadequate, Notepad++ has an option to search for Tabs by typing instead of typing them directly, and it also supports regular expressions.