Open WordPad from the Start menu. (Start-All Programs-Accessories-WordPad) Once it's open, click on "File" in the upper left, select "Open", then navigate to the file you want to open and double click on it. You may need to select a different "Files of Type" by using the drop down menu to choose .wri or .rtf but it depends on what type of file extension was on the previously saved file. That should cause WordPad to open the file instead of the new default association (MS Word) which opens the file when you double click on it.

Hope this helps.