I'm currently running Windows 7 Pro 64-bit, and after seeing ways to bring back the Start Menu, am going to take the plunge into Windows 8.1. My hard drive setup includes Windows running off an Adata 128GB SSD, while the majority of my data(documents,music, games) resides on my Toshiba 1TB hard drive. With such a set-up, would I be able to do a simple upgrade, or would this require a clean installation?