if you know someone with a retail vista dvd you could borrow it and run the start up repair on it ? I also used xp and 7 to do this but I don't recommend it and it did get me to desktop , ??
I hooked up the issue drive to a computer like as a storage drive and let the os on the working computer do the repairs to the issue drive .. it will also allow you to do a check disk
not to say its the correct thing to do but if its down to nothing else to loose .......