Starting Up with Last Known Good Configuration
When Windows completes booting process, the system configuration which is considered working and “good” is stored in the registry. If the current Windows session is problematic and you remember that the system was running flawlessly during the last session, you can reverse the changes by enabling the last good settings during startup.
Eject DVDs, CDs, floppy disks. Restart your computer and start pressing “F8” Key before Windows logo is displayed. Choose the operating system before pressing F8 if you have several OS on your computer. When “Windows Advanced Options Menu” appears on the black screen, select the “Last Known Good Configuration” option with the help of arrow keys and press Enter. If Last Known Good Configuration doesn’t remove system glitches use System Restore function to roll back configuration settings to the point in time when no errors occurred. System Restore changes can be undone. 
What Should I Know about Last Known Good Configuration?
-
Once chosen, Last Known Good Configuration option cannot be reversed (unless you used Safe Mode while starting up).
-
Last Known Good Configuration option won’t do anything to your personal files (documents, photos, emails stored on your computer). Only system configuration can be affected (the system data stored in the registry). Correspondingly, Last Known Good Configuration cannot restore lost files, neither can System Restore. Only specialized recovery programs can help in this situation. Install a recovery program right now, don’t wait for data loss accidents. You are not recommended to install any software on your computer after data loss.
