Word 97 file problems

HI there,
One of my users is having a problem opening Word 97 files on her PC. When she opens then through Word, the files appear garbled and unreadable. Yet, when the same file is opened through Windows Explorer, the document is unaffected. The PCin question is fully SP, for both NT and Word.
Any ideas why this is happening and how I can stop it?
Thanks again,
Craig