People lets get back to helping someone that's interested in trying Linux?
a) Raid0 is a poor choice for dual booting. The reason: if an OS is installed on a Raid0, it is spread across two drives. Installing another OS will destroy the Raid0 set up thereby making the first OS unbootable.
b) The comment about USB keyboards not working with Live CD/DVD is wrong. I'm dual booting XP / openSUSE 11 on one machine and Vista / Fedora/ Ubuntu / Dream Linux on my test machine. Ubuntu, Dream and Fedora were all installed from a Livecd while using a usb wireless keyboard.
c) If you don't have a lot of experience with Linux, then let Grub (the boot loader) install to it's default location. Whether your running Xp or Vista, any of the recently released Linux distros will pick it up and add it as a boot option in Grub.
Unfortunately, I think your screwed and will have to reinstall Vista if it was on a Raid0 and you installed another OS.