office xp/ excel/ macros

A user came up to me and is like the macros are not working in my 25+ page workbook. It was made in excel 97 and worked. Now we upgraded to office xp and not knowing what the user did the macros are not defined in this workbook. This is a monthlydocument and each one worked up until we got office xp. I have tried 12 different workbooks that were working last month and now when I am in excel and goto tools, macro, macros, there is nothing defined in the macro name field for any of these. What could have happened? Is this a setting in office xp? I am not sure how each of these documents have the macros missing when we were only in maybe 2-3 of them. Not knowing alot about office xp I am assuming the user selected something he shouldnt have and it affected the entire folder of excel documents...any feed back