I have one solution. Maybe you can try. As we know, Vista is base on NT6, not NT5 any more. Because windows xp bases on NT5, I am sure this version defferent and you can not use NT5 console apply to NT6, that is why it dosen't work. I think the only way to solution this is using VISTA original disk, boot from DVDROM, and setup step come to manage disk step. select Advance, and then delete the VISTA sytem partition. and then cancel the setup. restart your pc.