Excel opens two windows (2007 & 2003 format): I want only 2003.
 

I have a spreadsheet that must be edited under Win 7 and under Win XP.
Opening the file under Win 7 always gives two windows, the one marked
"Compatibility Mode" is up-to-date and the one worked with. The other is not
only useless to me, it is not even up-to-date. (I am willing to admit I may
have done something wrong to cause this condition). How do I get rid of this
unnecessary and confusing window?