Thanks again for the advice / info everyone. I am definitely going to play it safe with Win 7 Ultimate 64 bit. I've also discovered Zinstall Zpod, which lets me create a virtual machine on a thumb drive with my entire Windows 32 bit XP sp3 install from another old machine that I can plug into any Win computer and run XP on. This allows me to open old Sonar projects created in XP 32 bit should I ever need to bounce things out of them in Win 7 or future versions of Win I upgrade to. Finally, a really future-proof way to be able to still open old bundles flawlessly (I hope) or we shall see.