Unable to install Vista 64

I recently purchased an OEM copy of Vista 64 to install on my pc that currently has XP 32 and I can not get it to install. I do not wish to keep anything that is on my hard drive. I currently have a 160gb hard drive and have also recently purchased a 500gb hard drive. My plans were to use the 160gb drive as an install drive and to have the 500gb as an external storage drive. When I put the DVD in and restart my computer it does not recognize the disc and instead reboots into XP. I have changed the BIOS so that it would recognize the DVD and then it would ask to boot from cd when i said yes it would look like it was going to and then still boot into XP. So I decided to use the newly NTFS formatted 500gb hard drive that had nothing on it as the internal drive and to do a clean install of Vista on to it. When I did this I actually got the install disc to boot and got all the way past where I put the CD key in to where it asks me where I want to install Vista to. It will not recognize the drive. When I unplug either the 160gb or the 500gb and plug it into my extrnal enclosure it will read the drive but not allow me to install through the external drive because of the USB. It will not however recognize either of those drives internally like it says it needs to to install it on. I was kind of confused as where to go after here. Upon browsing the forums I saw stuff that was kind of related but nothing that really answered this question. Thanks in advance to any responses to this!

You may need to load drivers via F6 to have your hard drives recognized in setup... without knowing what board or chipset you have, I cannot be certain which drivers to recommend.