|Try an Open and Repair|
Open a new instance of Word,
This will bring you to the OPEN window
Select, and Highlight, but do not double click to actually open one of the problem files.
With the problem file highlighted, at the bottom of the OPEN window there should be an Open button with an arrow.
Click on the Arrow and a drop down list should appear, at the bottom of the drop down there should be a selection titled Open and Repair
See if that works.
Also, if you can open any of the problem files, try saving them in a different format such as HTML or RTF or even TXT.
If you can't open them with Word, try opening them with Notepad, Wordpad or a text editor like JEdit.
The top part of the file will look like garbage but if you scroll down, you should be able to recover the actual text.