Re format the drive and start again
to do this set your DVD/CDrom drive as your first drive
set your hard disk drive as your second drive typcially HDD0
or it may say C:
or even Hard disk drive
save the settings in the bios, then re boot the system make sure your windows vista dvd is in the drive, it will automatically load up follow the process for re formatting and re installing windows vista.
plenty of youtube videos on how to do it herehttp://www.youtube.com/watch?v=_rlVrasOnKo