I would still do a clean installation, as it is really the best way to ensure a stable system. You can then copy the necessary data over from Vista to W7. Although W7 is built on the fundamentals of Vista and can, in many cases where there isn't a specific W7 driver available use an equivalent Vista driver, it is still substantially different. It might well be possible to follow the upgrade path as described by Shawn (Brink), but in order to do that you really need an unadulterated installation of Vista. I note that you have made some tweaks to your Vista installation in order to speed it up, and it is possible that these are causing your W7 installation problems. You also need to remember that the current RC versions of W7 are the Ultimate editions, and, as such, are only officially supported as an upgrade from Vista Ultimate.