When I switched the 'preferred' parents to the correct ones, the wrong parents just disappeared from her yet they remained in their proper place in my master tree.
Like Denise, I don't know how this could have happened. I have not merged any files. At least, with your help, I now know how to fix it.
Now to determine why FTM2010 crashes without warning when I click on "index of individuals". Had to go back to an older backup file and still need to fill in the blanks on it.