I have successfully installed Windows 7 Professional 64 Bit on my HP which had a Vista Home Premium 32 Bit, from my 8GB USB drive as indicated above by kegobeer (Thanks!). But before I burnt a new image of the win 7 to a DVD on my MacBook Pro in order to transfer the files to the USB. I am wondering if this DVD burn was better, but then I noticed how fast was the installation from the USB was. System is running well so far. Thanks theog and kegobeer.