Dell XPS 8500

[sscsr1]

I am getting ready to do some house cleaning. I was going to do a restore on this system but just for kicks I was thinking I might want to upgrade to win 7 ultimate or at least pro. I ran rw everything on here and there is a slic tab that says ver 2.1. I have a installation dvd that installs the certs and all silently during install and will let me pick the version of win 7 I want but I think it is just for 32 bit and not 64. I am thinking that even if the dvd I have will do 64 bit, it just seems a little to easy for this to work just doing a reinstall from this dvd.

I would like to ask for any advice you may have on how to make this work. And any links I may need for like a 64 bit install for win 7 or what ever you may think of. I am kind of waiting to see what the consensus is here before I do anything.
Thank you for your time

Dell XPS 8500
Mother Board = unknown
RW = http://www.sendspace.com/file/5z3n8w