Perfomring a startup repair
I suggest you to Rebuild the BCD store manually by using the Bcdedit.exe tool.
To do this, follow these steps:
1. Put the Windows Vista installation disc in the disc drive, and then start the computer.
2. Press a key when you are prompted.
3. Select a language, a time, a currency, and a keyboard or another input method, and then click Next.
4. Click Repair your computer.
5. Click the operating system that you want to repair, and then click Next.
6. In the System Recovery Options dialog box, click Command Prompt.
7. Type Bootrec /RebuildBcd , and then press ENTER.
• If the Bootrec.exe tool runs successfully, it presents you with an installation path of a Windows directory. To add the entry to the BCD store, type Yes . A confirmation message appears that indicates the entry was added successfully.
• If the Bootrec.exe tool cannot locate any missing Windows installations, you must remove the BCD store, and then you must re-create it. To do this, type the following commands in the order in which they are presented. Press ENTER after each command.
Bcdedit /export C:\BCD_Backup
ren c:\boot\bcd bcd.old
8. Restart the computer.