Thanks everyone. I always do the backup first and I just checked them again. For some reason, some are listed as "files" and some are listed as "registration entries" Double left-clicking the file only gave me the option to "open with" and see what was there. Right clicking the registration entries does offer the merge option, but yesterdays backup only appeared as a file for some reason.
In any event, I did a system restore last night and everything's back to normal.