Back up all important data first. Then try out RegVac from
superwin.com
There is a Novice mode which helps too. In the worst case I'd (reluctantly) recommend that you delete the Office directories (all files in both Office 2000 and Office 97 versions) and run RegVac. Then reboot and install Office 97 fresh. {RegVac can undo everything it did as well - but it won't restore files you manually deleted.}
Start with backing up everything you consider important. Good luck.