A little more description would have helped.
Is the text all OK with just the non-printing symbols (spaces, tab,
paragraph marks, etc.) displayed? Press the ShowAll command button on the
toolbar (it looks like a reversed P) or use the keyboard shortcut
Ctrl+Shift+8.
If it is more serious than this, please describe and lets us in on the
version or Word and OS and if they are patched up to date.