Oh, I had only a few data (music, videos, documents) to back up, and I used one of your wonderfull tips ( found in another post ) to recover it.

I wish I was able to fix the old windows instead of re-installing and updating it, and reinstall all softwares ( MB and graphic card drivers, microsoft office, adobe CS2, … ) but this comp seemed to be in such a big mess. In any case I have hours to spend before it runs again :-\

Anyway, many thanks to your knowledge and patience.