>I have a macro that I want to put on every excel page.. in other word, I just want that the macro I created is accessible via any excel file that is open with a click of a button. I know how to create the button in excel using a macro, but I don't know how to create a file that will hold all the macros I need to work. I saw at some computer that I could put my macros in a file name perso.xls (or xla Idon't remember) but I can't seem to create the file or put it in a right place... how do we do this??

In theory this should work, but I haven't tried it:

You could put whatever macros you want in a file and save it as the normal template In office 200 I think it is C:\Program files\microsoft office\office\xlstart\normal.xlt
If that doesn't work try looking for how to change the normal template in help.

Put the macro for create the button in "Auto_open" for that template sheet.