i build ther rig in my sig with 2 320gb hdds, both partitioned 30/290 each and loaded xp on my first drive,30gb partition, i have an upgrade version of vista homer premium, so i can not just install vista on my second drive right? i have to upgrade an exisiting xp os, so can i reload xp on my second drive then upgrade it so i keep my first drive and xp untouched and run a dual boot system?

Wow where to begin well to answer your first question if you have Microsoft Windows Vista Home Premium UPGRADE no you can't which leads into into my second answer would yes you would need Windows XP or Windows 2000, or Vista Home Basic on your computer first then Microsoft Windows Vista Home Premium UPGRADE to upgrade to vista. But for me though I was never really fond of software with that title so I usually stuck with the complete version and never did an upgrade. Anyways to answer your Third question technically your can install Window's XP again on the same computer but since your using a different hard drive you would need to buy another copy of Windows XP because of that stupid license per device rule Microsoft has.

Man to think I was going to install vista on my laptop after I installed it on my pre built computer, well I guess I won't which I think is best in the long run for me anyways.