restore rows hidden in excel 2003 when using excel 2007
 

I had a fairly large workbook in 2003 (xls).
It had rows hidden in 3 of 4 sheets, and two hidden sheets.
When I opened it in 2007, I was unable to un hide the previously hidden rows
and sheets.
Fortunately I re installed 2003 and un hid all the rows and sheets and then
opened in 2007 and saved as xlsx.
Shouldn't 2007 have known that there were hidden rows and sheets?
Is ther a way to unhide without reinstalling 2003?