If you're on Windows, try opening WordPad (Start button > All Programs > Accessories > WordPad), then opening the file from within WordPad (i.e. File > Open). Or, if you're on a Mac, do the same thing but with TextEdit (Open a Finder window and go to Applications then TextEdit) instead of WordPad. If you're actually on Linux, then do pretty much the same thing with LibreOffice/OpenOffice.