Another option if you want to be amish and anti-techno is stay with XP and setup an Ubuntu install. I did this on my desktop, and after a bit of fooling use it now for any serious processing sessions. Runs 30% faster and laughs at any memory issues for mosaics etc (even with only 4GB total memory).
I really want to keep same OS on my work laptop, imaging laptop, home desktop as long as I can. My other motivation was always wanting to have had some experience with Linux, and prefering to spend my dollars on more astro-toys versus Micro$oft
PI still runs happily on the desktop and imaging laptop under XP as long as I don't expect miracles (e.g. work on OSC images or mosaic work)