In WinXP, Control Panel in Add/Remove programs, it should allow you to "repair" both WinXP and/or Office. The procedure is essentially the same as if you want to add or remove "options" for them. (Note however that it's been a few years since I've used XP and my memory is subject to erosion and environemental effects. Since I ran out of Jack a while back I think the environmental effects should be minimal.)

If you have an installation CD/DVD you should be able to reinstall (overlay) Word without affecting any of the documents. Since both WinXP and Office 200 are "beyond support" you should still be able to get security patches from Microsoft after a reinstall, but may not be able to get any "optional" patches.

System Restore is not really too reliable a way of "going back" since a complete new restore point is created any time ANY (even minor) "system change" occurs. The new restore point is recorded at the next reboot/restart. The newest restore point pushes the oldest one out and the oldest one is discarded. Only a few restore points are kept, and especially if you shut down frequently, only the latest half dozen restore points (that may all contain the same error) will be available.

If you have a backup, you might try copying a previously saved .doc back onto your drive, and see if it will open, although that's unlikely if the error is in Word. If you don't have a backup, I'd suggest getting a backup (external portable) drive and making one of what's left of the documents and images on your computer ASAP (?).

As noted, you can download Open Office (or the better "new replacement" for OO whose name I don't recall), and it should be able to open any of your .doc files. That should tell you whether your corruption is really in Word or if the files have gone away.

John