Question : Unable to format cells in Excel 2004

I have an excel document created in Excel 2003 on PC. On any PC I can format any cell, yet on Mac Excel 2004 I am unable to format any cell. If I add a new sheet to the document on the Mac then i am able to format cells in this sheet. I can also format any cell (on my Mac) of any other document that I create in windows. Please help me figure out what is wrong with this document

Answer : Unable to format cells in Excel 2004

Actually, which cells can you format? Using Excel 2003 I can't shade any cells on those sheets.