When starting the PC using the Last Known Good Configuration, your computer starts with the configuration from the last time your PC booted successfully. To do this, follow these steps:
- Click the Start button, then click the arrow next to Shut Down, then click Restart.
- As your computer starts, press and hold the F8 button. If the Windows logo appears, you'll need to try again by shutting down and restarting your computer.
- On the Advanced Boot Options screen, use the arrow keys to highlight Last Known Good Configuration (advanced), and then press Enter. Windows will start normally.
Boot sector viruses infect your computer before Windows starts. This may result in the error you're receiving. The Windows Defender Offline Beta tool will help remove boot sector viruses.
- On another computer, go to the Windows Defender Offline Beta site at: What is Windows Defender Offline Beta?
- Depending on your version of Windows, click Download the 32-bit version or Download the 64-bit version.
- If you're unsure of which version of Windows you are running, click the Start button, right click Computer, then left click Properties. The version will be listed next to System Type.
- When prompted, click the arrow next to Save, then click Save as. When the download is finished, remove the removable media.
- Insert a CD, DVD, or removable USB drive. On the left hand pane of the Save As window, click the removable media and click Save.
- Insert the Windows Defender Offline CD, DVD or USB in the PC infected with a virus or malware. Restart the PC.
- If your PC will detect the media automatically follow the steps below. If your PC doesn't detect media automatically, skip to step 7:
- Read the instructions on the screen to turn on this option. In some cases, you might need to press any key to start from the CD, DVD, or USB drive or to press a specific key, such as F12.
- Press the key (usually F12). A list of available devices is shown. There will be an entry for each hard drive, one for each CD, DVD drive, and a USB flash drive.
- Use the arrow key to scroll to the drive that has the bootable CD, DVD, or USB flash drive in it, and then press Enter.
- The PC will start from the Windows Defender Offline CD, DVD, or USB flash drive. The scan will take a few minutes and remove any malware that may be infecting your computer.
- If your PC will not detect the media automatically:
- During the restart process, read the screen for any instructions that explain how to interrupt normal startup and enter the BIOS Setup Utility. Most PCs use the F2, F10, ESC, or DEL key to begin the BIOS Setup.
- Look for a tab in the BIOS Setup Utility that is labeled Boot Order, Boot Options, or Boot. Following the directions on the screen, use the arrow keys to go to the Boot Order, then press Enter.
- Locate the CD, DVD, or USB flash drive (this might be called Removable Device) in the Boot list. Following the directions on the screen, use the arrow keys to move the drive up so that it appears first in the Boot list. Press Enter. The boot order sequence is now changed to boot from the CD, DVD, or USB flash drive.
- Press F10to save your changes and to exit the BIOS Setup Utility. Select Yes in the confirmation window. The PC will restart. Allow the PC to restart normally. The scan will take a few minutes and remove any malware that may be infecting your computer.
- After the scan is complete, the PC will boot into Windows normally.
Startup Repair can detect and fix certain types of system problems that might prevent Windows from starting.
To run Startup Repair using preinstalled recovery options:
- Restart your computer using the PC's power button. Do one of the following:
- If your computer has a single operating system installed, press and hold the F8 key as your computer restarts. You need to press F8 before the Windows logo appears. If the Windows logo appears, you need to try again by waiting until the Windows logon prompt appears, and then shutting down and restarting your computer.
- If your computer has more than one operating system, use the arrow keys to highlight the operating system you want to repair, and then press and hold F8.
- On the Advanced Boot Options screen, use the arrow keys to highlight Repair your computer, and then press Enter.
- Select a keyboard layout, and then click Next.
- On the System Recovery Options menu, click Startup Repair, and then follow the on screen instructions.
- Insert the Windows 7 installation disc or a system repair disc, and then shut down your computer.
- Restart your computer using the computer's power button.
- If prompted, press any key and then follow the instructions that appear.
- On the Install Windows page, or on the System Recovery Options page, choose your language and other preferences, and then click Next.
- If you're using the Windows installation disc, click Repair your computer.
- Select the Windows installation you want to repair, and then click Next.
- On the System Recovery Optionsmenu, click Startup Repair, and then follow the on screen instructions.
or (Windows Vista) What to do if Windows won't start correctly
For more information about Windows Update, visit: Windows Update
For more information about Windows Defender Offline Beta, visit: Windows Defender Offline FAQ