You may want to check Microsoft's
Mactopia downloads for Office X --- that will bring Word to 10.1.6
Usually, when Word stops works out of the blue, it's either corrupted Word preferences (although Office X and Office 2004 have been much better behaved in that respect than earlier versions of Word) or a corrupted font --- Word is the mine canary of font corruption on the Mac. Neither Disk Warrior nor Apple Hardware test will detect or fix such errors (although it's always good to have Disk Warrior verify the directory).
If you're running OS X 10.3 or later, you can use Font Book to check your fonts to see if any are shown as damaged, turning any such fonts off. If you're using an earlier OS X version, check
Version Tracker or
MacUpdate for compatible font utility / viewers such as
Font Sampler
(You can add details like OS version, CPU speed, Mac model, RAM, etc. to your posts using the My Settings link under your user name in the box on the right of the Discussions pages.)
You can check the preferences by logging on to a different account (create a troubleshooter user account if necessary in System Preferences> Accounts) and seeing if the same error occurs. If the test account is OK, then back in your normal user account, look for the Microsoft Word .plist files in ~/Users/ [yourusername]/ Library/ Preferences and with Word closed, move those to the desktop or Trash (you don't have to empty it ). Relaunching Word will create a new set of default prefs.
I'd also make sure that Word is beoing properly flagged as the default applications. Do Get Info on a Word document icon in the Finder ans check the Open With... field; select that, choose Other, browse to Word, select it, and check 'use for all such files' to reset the Mac's database accociating Word documents to the Word application.