You have a computer that runs Windows 7.
You have a system image backup of the computer.
You install a new application that is configured to run as a service.
You restart the computer and receive a STOP error message.
You need to successfully start Windows 7 in the minimum amount of time.
What should you do?
A. Start the computer from the Windows 7 installation media and select Startup Repair.
B. Start the computer and select Last Known Good Configuration from the advanced startup options.
C. Start the computer and select Safe Mode from the advanced startup options. Restore a restore point.
D. Start the computer and select Safe Mode from the advanced startup options. Restore the system image.
Correct Answer: B
Explanation/Reference:
Explanation:
Last Known Good Configuration (Advanced) ) feature in Advanced Boot Options is a recovery option that you use to start your computer with the most recent settings that worked. Last Known Good Configuration (Advanced) restores registry information and driver settings that were in effect the last time the computer started successfully. You should use the Last Known Good Configuration (Advanced) feature when you cannot start Windows 7 after you make a change to your computer, or when you suspect that a change that you just made is causing a problem, for example, if you cannot start Windows after you install a new video driver. When you start your computer by using the Last Known Good Configuration (Advanced) feature, Windows 7 uses the configuration stored in the following registry key:
HKEY_LOCAL_MACHINESystemCurrentControlSetXX (where by XX are numbers starting with 01 and rising in number to 02, 03, 04 and so on). This is the registry key that is used to store the configuration settings for the Drivers and Services on the system. Each time you boot the system, Windows will be assisted booting by using the registry key "HKEY_LOCAL_MACHINESystemCurrentControlSet" which will point to another control set key, normally
HKEY_LOCAL_MACHINESystemCurrentControlSet01, (depending on how the system is configured) which contains the setting for the current boot process. Each time Windows boots there will also be a values created under the "HKEY_LOCAL_MACHINESystemCurrentControlSetSelect" key.
These contain REG_DWORD data that enable the Control Keys to operate the way they are designed to. These values tell the CurrentControlSet key which numbered CurrentControlSet to point to enable Windows to boot successfully. The data that tells Last Good Known Configuration which numbered CurrentControlSet to load is also stored under these values. They also contain the data that tells Windows which CurrentContolSet not to use, as there is information stored that lets Windows know what CurrentControlSet has failed to load when Windows was unable to boot.
The Last Known Good Configuration CurrentControlSet will change each time the system configuration for the control set changes. This means that each time you install or uninstall a driver or service, a new numbered CurrentControlSet will be created and stored. If you alter the system, and it is then unable to boot, the Last Known Good Configuration will point to the CurrentControlSet that was last used in a successful boot.
This happens each time that Windows boots and there should typically be only four control sets, although it is not uncommon to have five or six of these
Control Sets contained in the registry. Windows will keep track of how many Control Sets are stored and should clear old ones once a certain amount is reached.
If installing a new program or device should render the system unbootable, you may be able to use "Last Known Good Configuration" to restore the damaged Control Set registry key with an earlier key that enabled the system to boot. This will remove the registry key(s) that relates to the problem driver or service. It will not remove the actual driver or service but will render it unusable. This could result in any program or device the was installed after the last boot having to be re-installed as their configuration setting will have been over written. When you perform a system restore following a normal boot or following a boot that uses the Last Known Good Configuration (Advanced) option, a restore point is created that enables you to undo the changes if they do not fix your problem. However, if you perform a system restore when the computer is in Safe Mode or by using the System Recovery options, you cannot undo the restore operation. In this case, if your problem is not resolved, you can run another system restore and choose a different restore point.