Windows XP and Windows 7 Dual Boot

The most important: See to that u install both the OS in same hard disk. U need to have two seprate drives for both OS. Install the one 1st,which u would like to give 1st priority and then the second one. For more detailed information follow this link http://lifehacker.com/5126781/how-to-dual-boot-windows-7-with-xp-or-vista