Bootloader repair commands have changed in Vista.
Boot the Vista DVD. Choose country. Next. Choose keyboard. Next.
Don't choose "install now" but "system recovery options". If it is proposed
to repair at the end of the search, answer "no". Deselect all lines and click
"next". Choose "command prompt".
Useful commands:
bootrec /fixmbr (rewrite master boot record)
bootrec /fixboot (repair bootloader components)
bootrec /rebuildbcd (rebuild bootloader configuration)
None of those will do any damage to the existing install, but unplug your working Vista disc to prevent it getting confused during a boot config rebuild.
PS Vista sucks
