I got some of this text from the MS support website.

This behavior may occur if Microsoft Windows does not properly associate .wps files with Word.
To resolve this issue, re-associate .wps files with Word. To do this, follow these steps. (Not sure exactly what your setup is, so your mileage may vary.)

1. Right-click Start, and then click Explore.
Windows Explorer starts.

2. Locate the .wps file that you want to open, and then right-click it.

3. Point to Open With, and then click Choose Program.
(If the Open With command is not available, click Open, click Select the program from a list, and then click OK.)

4. Click Microsoft Word.

5. Click to select the Always use the selected program to open this kind of file check box, and then click OK.

Then see if Word starts and opens the document.

Hope this helps.