How to start the Computer by using the last known good configuration

            If the startup problem occurs immediately after you make a change to the computer (for example, after you install a new driver), try to start the computer by using the Last Known Good Configuration feature. When you use the Last Known Good Configuration feature, you start your computer by using the most recent settings that worked. This feature restores registry information and driver settings that were in effect the last time the computer started successfully. Use this feature when you cannot start Windows after you make a change to the computer (for example, after you install or upgrade a device driver). To start the computer by using Last Known Good Configuration, follow these steps: 

Click Start, and then click Shut Down.
Click Restart, and then click OK. 

When you see the message Please select the operating system to start, press the F8 key. 

Use the arrow keys to select Last Known Good Configuration, and then press ENTER. Note NUM LOCK must be off before the arrow keys on the numeric keypad will function.

If you are running other operating systems on the computer, click Microsoft Windows Server 2003 in the list, and then press ENTER.
Notes
By selecting Last Known Good Configuration, you can recover from problems such as a newly added driver that may be incorrect for your hardware. This feature does not solve problems caused by corrupted or missing drivers or files. 

When you select Last Known Good Configuration, only the information in registry key HKLM\System\CurrentControlSet is restored. Any changes you have made in other registry keys remain. 

If you can start your computer by using Last Known Good Configuration, the last change that you made to the computer (for example, the installation of a driver) may be the cause of the incorrect startup behavior. Microsoft recommends that you either remove or update the driver or program, and then test Windows for correct startup.