I thought I post my first post here. I´ve been trying for several months to install and to run vista x64 and now I finally have ! My pimary problem have been my graphic card , ati radeon x1950. But this last time I tried to reinstall vista x64, there were a driver for my card at windows update, and I think that did the trick for me.
I also discovered that my "C" hd was faulty as well as another of my hds.
So that may also had an impact on my troublesome journey to a succesful installation of vista x64