Transcript 70-680_Lesson01

Troubleshooting Startup Problems
Lesson 6
Objectives
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Windows Boot Process
• If the system is running Windows 7, the system will
go through the following steps:
1. BOOTMGR is loaded and accesses the Boot
Configuration Data Store to display the boot
menu or to boot from a partition or volume.
2. WINLoad is the operating system boot loader
that loads the rest of the operating system.
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Windows Boot Process
3. NTOSKERNL.EXE is the main part of Windows,
which is responsible for various system
services, processes, and memory
management.
4. Boot-class device drivers implement a number
of functions that are utilized in different ways
by different hardware platforms based on
processor and chipset.
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Master Boot Record
• A master boot record (MBR) is the first 512-byte
boot sector of a partitioned data storage device
such as a hard disk.
• It contains the disk’s primary partition table, and
the code to bootstrap an operating system, which
usually passes control to the volume boot record
and uniquely identifies the disk media.
• By default, the master boot record contains the
primary partition entries in its partition table.
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Volume Boot Record
• A volume boot record (VBR), also known as a
volume boot sector or a partition boot
sector, is a type of boot sector, stored in a
disk volume on a hard disk, floppy disk, or
similar data storage device that contains
code for booting an operating system such
as BOOTMGR.
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System and Boot Partition/Volume
• The active partition is the partition or volume that is
marked as the partition to boot from. The active
partition or volume that contains the boot file
(BOOTMGR) is known as the system
partition/volume.
• The partition or volume that contains the Windows
operating system files (usually the Windows folder) is
called the boot partition.
• It is common for computer systems to have one drive
and one partition/volume, which makes the partition
both the system partition and the boot partition.
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%SystemRoot% Variable
• The %SystemRoot% variable is a special
system-wide environment variable found on
Microsoft Windows systems. Its value is the
location of the system folder, including the
drive and path. By default, on a clean
installation of Windows 7, the Windows files
are placed in the C:\Windows folder.
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Boot Configuration Data (BCD)
• Boot Configuration Data (BCD) is a firmwareindependent database for boot-time
configuration data used by Microsoft’s
Windows Boot Manager found with Windows
Vista, Windows 7, and Windows Server
2008.
• To edit the Boot Configuration, you would
typically use Bcdedit.exe.
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Bcdedit Command
• The Bcdedit.exe command-line tool can be
used to add, delete, and edit entries in the
BCD store, which contains objects. Each
object is identified by a GUID (Globally
Unique Identifier).
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Bcdedit Command
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Advanced Boot Menu
• When you have some problems that occur
during boot up, you may need to take some
extra steps to get the computer in a usable
state so that you can fix the problem.
• Since Windows XP, you can use the Advanced
Boot Menu to access advanced
troubleshooting modes.
• To access the Advanced Boot Options screen,
turn your computer on and press F8 before
the Windows logo appears.
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Advanced Boot Menu
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Advanced Boot Menu
• Repair Your Computer: Shows a list of
system recovery tools you can use to repair
startup problems, run diagnostics, or restore
your system. This option is available only if
the tools are installed on your computer’s
hard disk.
• Safe Mode: Starts Windows with a minimal
set of drivers and services. If you make a
change to the system and Windows no
longer boots, you can try safe mode.
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Safe Mode
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Advanced Boot Menu
• Safe Mode with Networking: Starts Windows in
safe mode and includes the network drivers and
services needed to access the Internet or other
computers on your network.
• Safe Mode with Command Prompt: Starts Windows
in safe mode with a command prompt window
instead of the usual Windows interface.
• Enable Boot Logging: Creates a file, ntbtlog.txt, that
lists all the drivers that are installed during startup
and that might be useful for advanced
troubleshooting.
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Advanced Boot Menu
• Enable low-resolution video (640×480): Starts
Windows using your current video driver and using
low resolution and refresh rate settings. You can
use this mode to reset your display settings.
• Last Known Good Configuration (advanced): Starts
Windows with the last registry and driver
configuration that worked successfully, usually
marked at the last successful login.
• Directory Services Restore Mode: Starts Windows
domain controller running Active Directory so that
the directory service can be restored.
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Advanced Boot Menu
• Debugging Mode: Starts Windows in an advanced
troubleshooting mode intended for IT professionals
and system administrators.
• Disable automatic restart on system failure: Prevents
Windows from automatically restarting if an error
causes Windows to fail. Choose this option only if
Windows is stuck in a loop where Windows fails,
attempts to restart, and fails again repeatedly.
• Disable Driver Signature Enforcement: Allows drivers
containing improper signatures to be loaded.
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System Configuration
• System Configuration (msconfig.exe) is a tool that
can help isolate problem startup programs or
services that prevent Windows from starting
correctly.
• When a problem occurs and assuming you can
successfully start and log in to Windows, you can
open System Configuration and disable certain
startup programs or services.
• If the problem goes away when you restart
Windows, you know that the problem is caused by
the program or service that you disabled.
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System Configuration
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Windows PE
• Windows Preinstallation Environment (Windows
PE) 3.0 is a minimal Win32 operating system with
limited services, built on the Windows 7 kernel.
• It is used to prepare a computer for Windows
installation, to copy disk images from a network file
server, and to initiate Windows Setup.
• Besides being used to deploy operating systems, it
is an integral component in recovery technology
with Windows Recovery Environment (Windows
RE).
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Windows Recovery Environment
• Windows Recovery Environment (WinRE) is a set of
tools included in the Windows Vista, Windows 7,
and Windows Server 2008 operating systems to
help diagnose and recover from serious errors,
which may be preventing Windows from booting
successfully.
• WinRE may be installed and/or booted from many
media including hard disks, optical media (such as
an operating system installation disc), and PXE
(e.g., Windows Deployment Services).
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System Recovery Options
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BootRec Command
• If you prefer to perform a manual repair, you
can use the BootRec command, which can
repair the MBR or the volume boot sector.
• BootRec.exe can be executed from the
Command Prompt in the System Recovery
tools.
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Skill Summary
• The computer goes through the power-on self-test
(POST), which initializes hardware and finds an
operating system to load.
– The system will search for a boot device (such as
a hard drive, optical disk, or USB flash drive) to
boot from.
• If the system is running Windows 7, the system will
load the BOOTMGR, WINLoad, and NTOSKERNL.EXE.
• BOOTMGR is loaded and accesses the Boot
Configuration Data Store to display the boot menu or
to boot from a partition or volume.
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Skill Summary
• WINLoad is the operating system boot loader
that loads the rest of the operating system.
• NTOSKERNL.EXE is the main part of
Windows that is responsible for various
system services, processes, and memory
management.
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Skill Summary
• A master boot record (MBR) is the first 512byte boot sector of a partitioned data
storage device such as a hard disk. It is used
to hold the disk’s primary partition table and
contains the code to bootstrap an operating
system, which usually passes control to the
volume boot record and uniquely identifies
the disk media.
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Skill Summary
• A volume boot record (VBR), also known as a
volume boot sector or a partition boot
sector, is a type of boot sector, stored in a
disk volume on a hard disk, floppy disk, or
similar data storage device that contains
code for booting an operating system such
as BOOTMGR.
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Skill Summary
• The active partition is the partition or volume that is
marked as the partition to boot from. The active
partition or volume that contains the boot file
(BOOTMGR) is known as the system partition/volume.
• The partition or volume that contains the Windows
operating system files (usually the Windows folder) is
called the boot partition.
• Boot Configuration Data (BCD) is a firmwareindependent database for boot-time configuration data
used by Microsoft’s Windows Boot Manager found with
Windows Vista, Windows 7, and Windows Server 2008.
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Skill Summary
• To edit the Boot Configuration, you typically
use Bcdedit.exe.
• To access the Advanced Boot Options
screen, turn your computer on and press F8
before the Windows logo appears.
• Last Known Good Configuration starts
Windows with the last registry and driver
configuration that worked successfully,
usually marked at the last successful login.
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Skill Summary
• Safe mode is useful for troubleshooting problems
with programs and drivers that might not start
correctly or that might prevent Windows from
starting correctly.
• System Configuration (msconfig.exe) is a tool that
can help identify problems that might prevent
Windows from starting correctly.
• Windows Preinstallation Environment (Windows PE)
3.0 is a minimal Win32 operating system with
limited services, built on the Windows 7 kernel.
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Skill Summary
• Windows Recovery Environment (WinRE) is a set of
tools included in the Windows Vista, Windows 7,
and Windows Server 2008 operating systems to
help diagnose and recover from serious errors that
may be preventing Windows from booting
successfully.
• The Startup Repair tool, which is part of the System
Recovery tools is capable of fixing almost any
startup problem related to boot sectors, MBRs, or
the BCD registry file.
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Skill Summary
• To perform a manual repair, use the
BootRec command to fix the MBR or the
volume boot sector.
• You should always keep in mind that while
these repairs can come in handy and save
you a lot of time and effort, they do not
replace a good backup.
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