Arf, I did the wrong thing before I post that thread, I reinstall + gigaclean so no clues left, just that corrupt project, I'be opened it with notepad but I only see the first instrument, the rest is full of "nul" tags.
Gigastudio sometimes give me that message when I try to open that corrupt project :
"the file ... seem to be corrupted,.., try to replace or rebuild it" that's why I thought there was a way to rebuild it.
Thanks a lot cm for your help if I ever have this problem again I'll think about that useful tip !
I just need a way to read which instruments I used that would be great after that fx or plugs won't matter