Help! Excel 2007 and Excel 2003 are not compatible?

Hi all,

I just don't understand this.

I have a Excel sheet which was created in Excel Xp 2003. And it is
full of calculations.

When I open it in Excel 2007,

And press SHIFT+F9, it always gives "NO-CELL" error.

Basically it doesn't run at all.

But when I go to each cell, and following the logical dependency, and
refresh/recalculate each cell one by one,

then the results are correct...

But there are so many cells and manually going through them are
infeasbile.

What can I do now?

Can anybody help me?

Thanks!