i have dell xps 1530 lapop which came with preinstalled vista. i am having 3 hard disk, c: having vista, d: recovery, i have partitioned e: to have xp. but during installation of xp, the following error comes "Setup did not find any hard disk drives installed in your computer. Make sure any hard disk drives are powered on and properly connected to your computer and that any disk related hardware configuration is correct. This may involve running a manufacture supplied diagnostic or setup program. Setup cannot continue. To quit setup, press F3".. What should i do?What program did you use to setup E: ? ?
Did you make it an EXTENDED partition ? ?
Has it been formatted yet ? ? Windows won't SEE it until it is...Who! Before you go any further, trying to install XP after Vista will invite trouble. If I had what you have, here is what I would try. Pull out the Vista drive and set it aside in a sage place. PUT another drive in the first POSITION on the PC. Install XP the usual way. Then when I am happy with that, I would consider finding a boot manager program that will make it easy to have both drives in the PC at the same time. There are some free ones out there that will do that just fine. I suspect the reason XP can not see you hard drive is that you probably have a new SATA hard drive, which was introduced after XP was written. I have read that to install XP on a SATA hard drive you must install a special driver that you must download from the computer maker or the hard drive maker’s web site. I have no first hand experience with this PROBLEM, so I hope another forum reader will provide more information. Confirm whether your computer has a SATA drive and try a Google search for installing XP on SATA.

The other difficulty you may face is that dual-booting a computer by installing an older operating system after a newer one will not create a proper boot loader. Here is an excellent tutorial on installing XP after Vista.
http://www.howtogeek.com/howto/windows-vista/install-windows-xp-on-your-pre-installed-windows-vista-computer/To Install windows XP on newer machine, go to bios settings and under onboard settings change to ata mode. Then you should be Fine to install Windows XP.