1. Use the Windows Recovery Environment (WinRE) to run System Restore
1) Insert the Windows Vista installation disc into the disc drive, and then start the computer.
2) Press a key when the message indicating "Press any key to boot from CD or DVD …". appears.
3) Select a language, a time and currency, and a keyboard or input method, and then click Next.
4) Click Repair your computer.
5) In the System Recovery Options dialog box, choose the drive of your Windows installation and click Next
6) At the System Recovery Options Dialog Box, click on System Restore.
7) Follow the System Restore Wizard instruction as usual and choose the appropriate restore point.
8) Click Finish to restore the system.
2. If it doesn't work, let's try Startup Repair from the Windows Recovery Environment (WinRE)
1) Insert the Windows Vista installation disc into the disc drive, and then start the computer.
2) Press a key when the message indicating "Press any key to boot from CD or DVD …". appears.
3) Select a language, a time and currency, and a keyboard or input method, and then click Next.
4) Click Repair your computer.
5) In the System Recovery Options dialog box, choose the drive of your Windows installation and click Next.
6) At the System Recovery Options Dialog Box, click on Repair your computer.
7) (Click the operating system that you want to repair), and then click Next.
8) In the System Recovery Options dialog box, click Startup Repair.
Note: If you don't own a Windows Vista installation disc, you can download the ISO file at the supplied link, and make a Bootable Disk from it. For detail information, please visit the following website:
http://neosmart.net/blog/2008/windows-vista-recovery-disc-download/