Windows 7: Recovering from a Problem

Recovering from a Problem

Ideally, solving a problem will require a specific tweak to the system: a Registry setting change, a driver upgrade, a program uninstall. But sometimes you need to take more of a “big picture” approach to revert your system to some previous state in the hope that you’ll leap past the problem and get your system working again. Windows 7 offers three ways to try such an approach: last known good configuration, System Restore, and System Recovery Options (which you should use in that order).

Booting Using the Last Known Good Configuration

Each time Windows 7 starts successfully in Normal mode, the system makes a note of which control set—the system’s drivers and hardware configuration—was used. Specifically, it enters a value in the following Registry key:

HKLM\SYSTEM\Select\LastKnownGood

For example, if this value is 1, it means that control set 1 was used to start Windows 7 successfully:

HKLM\SYSTEM\ControlSet001

If you make driver or hardware changes and then find that the system won’t start, you can tell Windows 7 to load using the control set that worked the last time. (That is, the control set that doesn’t include your most recent hardware changes.) This is the last known good configuration, and the theory is that by using the previous working configuration, your system should start because it’s bypassing the changes that caused the problem. Here’s how to start Windows 7 using the last known good configuration:

Recovering Using System Restore

The Last Known Good Configuration option is most useful when your computer won’t start and you suspect that a hardware change is causing the problem. You might think that you can also use the last known good configuration if Windows 7 starts but is unstable, and you suspect a hardware change is causing the glitch. Unfortunately, that won’t work because when you start Windows 7 successfully in Normal mode, the hardware change is added to the last known good configuration. To revert the system to a previous configuration when you can start Windows 7 successfully, you need to use the System Restore feature.

To revert your system to a restore point, follow these steps:

1.	Select Start, type restore, and then select System Restore in the search results. Windows 7 displays the System Restore dialog box.
2.	The first System Restore dialog box (see Figure 1) offers two options: Recommended Restore— Activate this option to restore Windows 7 to the restore point shown (which is usually the most recent restore point). Skip to step 5. Choose a Different Restore Point— Activate this option to select from a list of restore points. Click Next and continue with step 3. Figure 1. The initial System Restore window offers two restore options
3.	If you don’t see the restore point you want to use, click to activate the Show More Restore Points check box, which tells Windows 7 to display all the available restore points, as shown in Figure 2. Figure 2. Use this dialog box to choose the restore point you want to revert to. Note By default, Windows 7 displays only the restore points from the previous 5 days. When you activate the Show More Restore Points check box, you tell Windows 7 to also show the restore points that are more than 5 days old.
4.	Click the restore point you want to use. There are seven common types of restore points: System— A restore point that Windows 7 creates automatically. For example, the System Checkpoint is the restore point that Windows 7 creates each day or when you boot your computer. Critical Update— A restore point set prior to installing an important update. Install— A restore point set prior to installing a program or optional update. Uninstall— A restore point set prior to uninstalling a program or update. Manual— A restore point you create yourself. Undo— A restore point set prior to a previous use of System Restore to revert the system to an earlier state. Unknown— Any restore point that doesn’t fit in the above categories.
5.	Click Next. If other hard disks are available in the restore point, Windows 7 displays a list of the disks. Activate the check box beside each disk you want to include in the restore, and then click Next.
6.	Click Finish. Windows 7 asks you to confirm that you want your system restored.
7.	Click Yes. System Restore begins reverting to the restore point. When it’s done, it restarts your computer and displays a message telling you the results of the restore.
8.	Click Close.