update problems

I have a client who has an updated from ME version of XP Home…..Seems that one by one his files and programs are becomming corrupted (Word was the 1st to go) and ceasing to work. I looked into it and found that some of the updates from Microsoftwill do this on an updated version due to a registry difference. I told him to diable his auto update and switch it to notify.
Has anyone else had these problems and found fixes or is it time to reinstall.