Hi there,
Give the group as much specific info about this problem as you can. When did it begin malfunctioning, do you have other Office applications on your main computer, what happens if you try to open it from within Word, does the same thing happen with say Excel, or Outlook, will it open when you right click on the document and click "open", what is the version of Word or Office you have? Lastly, are there any other components of Word or Office that don't seem to function as expected?
With more specific info, someone will be able to get you going.