How to load last known good configuration
The "Last Known Good Configuration" option was first introduced in Microsoft Windows 2000 and is available in all later versions of Windows including Windows XP. This feature enables a user to load the last working version of Microsoft Windows. This is a great step to try when trying to fix issues with a computer not being able to load into Windows.
Tip: If you can open Normal Mode or Safe Mode try restoring Windows back to an earlier copy.
To load the last known good configuration in Windows 2000 or XP reboot the computer and as it's booting booting repeatedly press the F8 Key, which should bring up the "Windows Advanced Options Menu" as shown below. Use your arrow keys to move to "Last Known Good Configuration" and press your Enter key.
Trouble Getting into Windows 2000 or Advanced Options menu - If after several attempts you are unable to get into Windows 2000 or Windows XP Safe Mode as the computer is booting into Windows turn off your computer. When the computer is turned on the next time Windows should notice that the computer did not successfully boot and give you the Safe Mode screen.
Windows Advanced Options Menu
Please select an option:
Enable Boot Logging
Start Windows Normally
Use the up and down arrow keys to move the highlight to your choice.
As can be seen from the above example, you should be able to highlight and press enter to load the last known good configuration. Once completed the computer should restart and load into Windows.
Will running the Last Known Good Configuration delete anything?
No, running the last known good configuration will restore your last good system settings and will not delete anything. The only thing you may have to reinstall programs you have recently installed because the configuration for those programs may have been lost.