As The Piney has asked, more information is required.
If windows Vista isnt bootable or fails to boot or something is corrupt you can use the following guide to repair the installation: http://www.vistax64.com/tutorials/88236 ... vista.html
Tho if something is corrupt, then you may need a new HDD or need to run a 'check disk' before repairing windows. Again this depends on the problem you are having.
Visit the UBCD Wiki: http://wiki.ultimatebootcd.com
Please check your UBCD
ISO MD5 Hash Sum
; May prevent issues later on by not having an exact copy.
Currently Working on Common Issues and Repair Tips
on the Wiki.