After you install a device or update a driver for a device, Windows Vista or Windows 7 may not start

Start Windows Vista or Windows 7

1. If you installed a new device, remove the device, and then try to start the computer. If the operating system does not start, go to step 2. If the operating system starts, go to the "Resolve the cause of the startup problem" section of this article.
2. Start the computer, and then press F8. On the Advanced Boot Options screen, select Last Known Good Configuration, and then press ENTER. If the operating system does not start, go to step 3. If the operating system starts, go to the "Resolve the cause of the startup problem" section of this article.
3. Start the computer, and then press F8. On the Advanced Boot Options screen, select Safe Mode, and then press ENTER. If the operating systemstarts in safe mode, go to the "Resolve the cause of the startup problem" section of this article. If you cannot start the operating system in safe mode, go to the "Use the Windows Recovery Environment to repair Windows Vista or Windows 7" section of this article.

Use the Windows Recovery Environment to repair Windows Vista or Windows 7

To use the Windows Recovery Environment, you must have the Windows Vista or Windows 7 installation disc. To start the Windows Recovery Environment, follow these steps:

1. Put the installation disc in the disc drive, and then start the computer.
2. Press a key when you are prompted.
3. Select a language, a time and currency, and a keyboard or input method, and then click Next.
4. Click Repair your computer.
5. In the System Recovery Options dialog box, click the operating system that you want to repair, and then click Next.

Use the tools in the Windows Recovery Environment to repair Windows Vista or Windows 7. To do this, follow these steps:

1. If the computer will not start in safe mode, click Startup Repair in the System Recovery Optionsdialog box to fix certain problems that may prevent the operating system from starting correctly. If the Startup Repair tool cannot diagnose or repair the problem, go to step 2. If Windows Vista or Windows 7 starts, go to the "Resolve the cause of the startup problem" section.
   
   For more information about how to use Startup Repair, click the following article number to view the article in the Microsoft Knowledge Base:
    
   925810 A Stop error occurs, or the computer stops responding when you try to start Windows Vista or Windows 7
2. In the System Recovery Options dialog box, click System Restore to restore the operating system to the restore point that was created when the program or the driver was installed. If you cannot use the System Restore tool to start the computer, go to step 3.
3. Use the Command Prompt option in the Windows Recovery Environment to disable the driver that stops the operating system from starting. To do this, follow these steps.
   1. In the System Recovery Options dialog box, click Command Prompt.
   2. Type the following commands. Press ENTER after you type each command.
      cd \Windows\INF
      notepad setupapi.app.log
   3. Note the date at the start of each new device or driver installation section. Use these dates to determine the last driver that was installed.
   4. After you determine which driver was installed last, determine whether the driver is required to start the computer. To do this, read the information in the section of the Setupapi.app.log file that describes this driver. If the driver is related to the disk controller or to the chipset, or if the driver is provided by the operating system, search for the driver name and for the symptom of the problem on the following Microsoft Web site:
      http://www.microsoft.com
      Determine whether the driver can be disabled before you continue. If the last driver that was installed is not required to start the computer, go to step e.
   5. At the command prompt, type regedit, and then click OK.
   6. Click HKEY_LOCAL_MACHINE, and then click Load Hive on the File menu.
   7. Locate and then click the C:\Windows\System32\Config\System file, and then click Open.
   8. In the Load Hive dialog box, type Offline, and then click OK.
   9. Expand System, and then click Select.
   10. In the right-pane, locate Current, and then note the value in the Data column.
   11. Expand ControlSet00x, and then expand Services. x is the value from the
       Data column that you noted in step j.
   12. Locate the subkey that corresponds to the last driver that was installed. If you cannot locate a match, click Services, click Find on the Edit menu, type the name of the driver in the Find what box, and then click Find Next.
   13. Click the subkey that has the driver name.
   14. In the right-pane, right-click Start, and then click Modify.
   15. In the Value data box, type 4, and then click OK. This step stops the driver from starting.
   16. Locate and then click the following registry subkey:
       HKEY_LOCAL_MACHINE\Offline
   17. On the File menu, click Unload Hive, and then click Yes in the Confirm Unload Hive dialog box.
   18. Exit Registry Editor.
   19. Restart the computer.
   20. If the operating system does not start, start the Windows Recovery Environment, and then repeat step a through step s. You may have to repeat these steps until all the drivers that have been installed since the last successful startup are disabled.
4. When you can start the operating system, contact the manufacturer of the device or of the driver for information about compatibility issues or updates that may be available.

Resolve the cause of the startup problem

1. Open Device Manager. To do this, click Start , type Device Manager in the Start Search box, and then click Device Manager in the Programs list.
2. If you updated the driver for a device, right-click the device in Device Manager, click Properties, and then click Roll Back Driver on the Driver tab.
3. If you installed a new device, right-click the device in Device Manager, and then click Uninstall.
4. If you installed a program that includes the new driver, follow these steps:
   1. Click Start , type appwiz.cpl in the Start Search box, and then click appwiz.cpl in the Programs list.
   2. Click the name of the program that was installed, and then click Uninstall/Change.
       If you are prompted for permission to continue, click Continue.
   3. When you receive a "Do you wish to proceed" message, click Yes.
5. Restart Windows Vista or Windows 7.