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 systems recovery options dialog box, choose the drive of your Windows installation and click next.
6. At the systems 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.