I think .wps is a Microsoft Works word processor file.  Works has
changed file formats over the years... do you know what version of Works
was used to create the file?  Word 2003 includes a converter that opens
Works 7.0 files.  In Word, when you click on File | Open, one of the
choices under "Files of type" should be Works 7.  If you don't see it,
then install the converter from your Word/Office 2003 CD by clicking on
Start | Control Panel | Add/Remove Programs | Microsoft Office 2003 |
Change.  If you need the older Works 6.0 converter, see
http://support.microsoft.com/?kbid=315757.

If the file you have is actually a WordPerfect file, then Word 2003
includes a converter for WordPerfect 6.x for Windows, which will open
WordPerfect 6.x thru 12 files.  Similary, if you don't see WordPerfect
6.x for Windows as a choice under "Files of type" in File | Open, then
install the converter from your Word/Office CD.