the topic title sounds confusing, let me elaborate.. I have 2 HDD, one is IDE and the other is SATA. My primary HDD is SATA which I installed vista and use it for my daily work. now my IDE is an old one, I took it from my old computer and so, plan to use it on my new computer. Since its possible to use IDE and SATA together right? well i assume they are.. now, I was just wondering if I installed my IDE hdd on my new computer and Installed XP? thats what we call dual boot right? and so, Do i have to get to choose which OS should I use in the startup boot? and lastly If i managed to make it both work. Since my primary OS is Vista, will i be able to access my IDE hdd (XP) files from vista?