I have built my own computer with an ASUS P5K Deluxe WIFI motherboard, E6750 CPU w/1333 FSB, Intel P35 chip and 4 GB DDR2 memory running on Vista Ultimate 32bit. I want to upgrade my CPU with a quad core CPU, and possibly doing a complete reinstall so I can install my 64 bit Vista Ultimate. If I would install the 64 bit system, I would also install 8 GB DDR2 memory. My purpose for this is to speed up my computer. I do a lot of digital imaging work, movie making, etc, as a hobby. My questions are 1. If I decide not to change my OS and just upgrade from a Core 2 duo to a Core 2 quad, do I have to reinstall my OS, or just reboot? 2. Would you recommend upgrading from a 32 bit to a 64 bit Vista system? I would rather wait a year for Windows 7. Thanks, Bill