Simple to install, not so simple to implement.
After installing the drive into the cae, and "hooking it up," in the BIOS, set the drive boot order to SATA first, then IDE, if possible.
Now, setting up a "Dual Boot" system is not that easy. Research online! Especially if one of the OS is Win7. It will involve Boot Manager Record tweaks, of which there are apps out there to do it.
Sorry, I used to have a link to a great webpage about setting up a dual boot system, but have since lost it. I gave up on the dual boot setup of WinXP and Win7, I didn' t need XP anymore.