If the Excel macros were routines you could use globally (without knowingly having to open a specific workbook) then it is very likely that they were either saved in Personal.xls or in an add-in file (with an .xla extension).

Personal.xls would be stored in Excel's start-up folder, typically found under:
C:\Documents and Settings\<user name>\Application Data\Microsoft\Excel\XLSTART

An .xla file could be stored anywhere, but a likely bet would be
C:\Documents and Settings\<user name>\Application Data\Microsoft\AddIns



However, if each macro was specific to a certain workbook then it is likely it was stored within that workbook itself.