If you're not able to access any of the F8 options you can still access Vista's Recovery Console if you have the Vista installation DVD.  (The F8 menu should have a 
If no Vista Installation DVD I'm not certain if other versions of windows chkdsk and recovery console will work under Vista. AFAIK, The NTFS file format is the same, but perhaps there's some differences in earlier and later versions of windows. (You may be able to attempt to repair the Vista installation with other Windows Versions of Recovery Console.)
XP recovery console was fairly simple. If the boot partition and/or boot files became corrupted I normally booted to a "Recovery Console" installation and issued the fixmbr (boot drive), bootcfg (boot drive), chkdsk (boot drive) and others 
However when running chkdsk you need to be careful as if you choose to repair a boot partition. When chkdsk finds any corrupted file(s) and/or file structure it will move corruption to special folders while trying to perform repairs.
There are some free or freeware repair and rescue utilities, some may use Linux as a boot rescue OS. I can't remember their exact names but remember using them.
Here is a utility that should also work if you don't have access to  Windows "Recovery Console" (which should be also installed on any OEM  rescue partition.) The  cost for this rescue app. is around $20.00.
 that is a command-line tool for managing  BCD stores. It can be used for a variety of purposes, including creating  new stores, modifying existing stores, adding boot menu options, and so  on.
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Attrib
 
Changes the attributes of a file or directory.[/TD]
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Batch
 
Executes the commands specified in the text file.[/TD]
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Bootcfg
 
Boot file (boot.ini) configuration and recovery.[/TD]
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ChDir (Cd)
 
Displays the name of the current directory or changes the current directory.[/TD]
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Chkdsk
 
Checks a disk and displays a status report.[/TD]
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Cls
 
Clears the screen.[/TD]
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Copy
 
Copies a single file to another location.[/TD]
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Delete (Del)
 
Deletes one or more files.[/TD]
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Dir
 
Displays a list of files and subdirectories in a directory.[/TD]
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Disable
 
Disables a system service or a device driver[/TD]
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Diskpart
 
Manages partitions on your hard drives.[/TD]
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Enable
 
Starts or enables a system service or a device driver.[/TD]
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Exit
 
Exits the Recovery Console and restarts your computer.[/TD]
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Expand
 
Extracts a file from a compressed file.[/TD]
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Fixboot
 
Writes a new partition boot sector onto the specified partition.[/TD]
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Fixmbr
 
Repairs the master boot record of the specified disk.[/TD]
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Format
 
Formats a disk.[/TD]
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Help
 
Displays a list of the commands you can use in the Recovery Console.[/TD]
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Listsvc
 
Lists the services and drivers available on the computer.[/TD]
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Logon
 
Logs on to a Windows installation.[/TD]
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Map
 
Displays the drive letter mappings.[/TD]
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Mkdir (Md)
 
Creates a directory.[/TD]
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More
 
Displays a text file.[/TD]
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Net Use
 
Connects a network share to a drive letter.[/TD]
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Rename (Ren)
 
Renames a single file.[/TD]
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Rmdir (Rd)
 
Deletes a directory.[/TD]
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Set
 
Displays and sets environment variables.[/TD]
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Systemroot
 
Sets the current directory to the systemroot directory of the system you are currently logged on to.[/TD]
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Type
 
Displays a text file.[/TD]