Logo
programming4us
programming4us
programming4us
programming4us
Home
programming4us
XP
programming4us
Windows Vista
programming4us
Windows 7
programming4us
Windows Azure
programming4us
Windows Server
programming4us
Windows Phone
 
Windows Vista

Supporting Desktop Applications : Repair a Corrupted Operating System (part 1)

- Windows 10 Product Activation Keys Free 2019 (All Versions)
- How To Bypass Torrent Connection Blocking By Your ISP
- How To Install Actual Facebook App On Kindle Fire
3/20/2011 11:09:00 AM
Application support involves not only supporting applications, but also supporting the underlying operating system. Application availability in a Microsoft environment depends on a functioning operating system. This makes understanding system recovery a requirement if you are supporting desktops in an enterprise.

System recovery is always a juicy topic on certification exams. You simply must know how to recover from a catastrophic event. The first thing to do when you discover that the computer is failing is to define what was happening just before the failure occurred. This usually provides you with the insight required to troubleshoot the problem. The exam describes recent events of a system, just prior to its failing. Based on this information, you are required to define what corrective action should be taken to recover the system.

A system failure can be a failed startup in which Windows Vista begins to boot up but then hangs at either a black screen or perhaps even a blue screen stop error. Such failures might be due to startup errors and could be caused by newly installed applications or device drivers, corrupted boot or system files, or improper edits of configuration or Registry files.

Failures can occur after the system has booted and while the console is idle, where the computer hangs or “blue screens.” This failure could be caused by a device failure or by corrupted system files.

Failures can also occur during the operation of an application, again where the computer hangs or “blue screens.” Such failures might be caused by incomplete application installation, application incompatibility with Windows Vista, or corrupted application or system files.

These are just some examples illustrating where you can begin your troubleshooting and repair procedures.

Last Known Good Configuration (LKGC)

The Last Known Good Configuration (LKGC) has been around since the NT days. This tool can be and is effective in restoring a system to a functional state under certain circumstances. The LKGC is an archived copy of the computer’s Registry the last time a successful bootup and user logon occurred. The LKGC is declared “good” and is archived each time a user successfully logs on.

You access and implement the LKGC during the initial bootup process by pressing the F8 function key while the gray-on-black Startup menu is being displayed on the computer. You then enter into the Advanced Boot Options, where several recovery options are presented, including LKGC, as shown in Figure 1.

Figure 1. Access the Advanced Boot Options menu by pressing F8 during the Startup menu.

Simply select LKGC from the Advanced Boot Options menu and press Enter. This deletes the current copy of the system’s Registry, reinstalls the previous copy of the Registry, and proceeds to boot up the replaced Registry files.

There may be other combinations in which LKGC does or does not work, but these examples cover the vast majority of the situations that steer you toward or away from LKGC as a repair mechanism.

Safe Mode

If LKGC is not the appropriate repair mechanism, no worries; you have options. The next repair option to consider is Safe Mode. Safe Mode starts Windows with only the core drivers and services. This capability can be useful when the system fails to boot up after installing new device drivers. Because you are loading only a basic set of drivers during bootup in Safe Mode, if a driver is the cause of the failure, it is likely that you will be able to boot the system into a (semi) functional operating system. Now you can access the system and begin to perform your repairs by uninstalling drivers or whatever caused the problem.

Alert

LKGC is useful in repairing a failed computer in the following situations:

  • A user changes Registry settings using a script or by using the RegEdit or RegEdt32 utilities. (These two command-line executables launch the same Registry Editor tool in Windows Vista. In earlier versions of Windows, they were two different tools.) Upon reboot, the computer fails.

  • A user installs a new application that makes Registry changes, causing the computer to fail.

  • A user installs new drivers for a new device that makes Registry changes, causing the computer to fail. You probably need to remove the new device in addition to invoking the LKGC.

  • A user upgrades an existing application, causing the computer to fail. The upgrade installs files with different names or to different paths than the original version. Because the old copy of the Registry points to original files that still exist and have not been overwritten, the old Registry “rolls back” the computer to its prior state.

  • A user upgrades drivers for an existing device, causing the computer to fail. The upgrade installs files with different names to different paths than the original version. Because the old copy of the Registry points to original files that still exist and have not been overwritten, the old Registry “rolls back” the computer to its prior state.

LKGC is not useful in repairing a failed computer in the following situations:

  • A user upgrades an existing application, causing the computer to fail. The upgrade installs files with the same names to the same paths as the original version. Because the old copy of the Registry still points to filenames that have been overwritten and are now the failing files, the old Registry does not return the computer to a functional state.

  • A user upgrades drivers for an existing device, causing the computer to fail. The upgrade installs driver files with the same names to the same paths as the original version. Because the old copy of the Registry still points to driver filenames that have been overwritten and are now the failing files, the old Registry does not return the computer to a functional state.

And as always, LKGC can no longer help recover a computer after a user successfully logs on because the Registry configurations are synchronized to the current logon.


Caution

Safe Mode and Mass Storage Safe Mode does install all mass storage device drivers. If the new driver that caused the failure was for a CD-ROM drive, DVD drive, tape drive, controller card, or other mass storage device, Safe Mode does not solve your problem.


You can access Safe Mode on the Advanced Boot Options by pressing the F8 function key while the gray-on-black Startup menu is being displayed. You have three different boot options:

  • Safe Mode— Core drivers and mass storage device drivers only

  • Safe Mode with Networking— Adds NIC drivers to provide network connectivity

  • Safe Mode with Command Prompt— Launches the command prompt

Alert

Safe Mode is useful in repairing a failed computer in the following situations:

  • A user installs or upgrades device drivers (other than mass storage device drivers) that cause the computer to fail during bootup.

  • A user configures an incompatible video refresh rate or display setting.

  • A user installs an application causing a stop error, and the application inserts some or of all of its services at bootup of the operating system or a user’s logon.


Boot Configuration Data

MS-DOS used the files IO.SYS, MSDOS.SYS, CONFIG.SYS, COMMAND.COM, and AUTOEXEC.BAT to boot the operating system.

Windows NT, 2000, 2003, and XP used NTLDR, Boot.ini, and NTDetect.com to boot the system.

Vista (and eventually Server 2008) uses the Boot Configuration Data (BCD) architecture to boot the system. This is to accommodate the new replacement for the PC/AT BIOS that you have come to know and love. The new boot process replacement for the PC/AT BIOS is called the Extensible Firmware Interface (EFI). BCD supports booting from the current PC/AT BIOS firmware, as well as the upcoming EFI firmware-based computers.

Occasionally, the boot instructions for a computer get corrupted or, for other reasons, fail to boot the operating system properly. When this happens, you must repair these boot instructions. In the case of Windows Vista, these instructions reside within the BCD data.

BCD data is not stored in textual format and is therefore not directly human readable. It is stored in a protected region of the Registry, but should not be accessed through the Registry Editor application. Microsoft has provided a nifty new tool called BCDedit ( BCDedit.exe) to manipulate the contents of the BCD.

To access this tool, get to a command prompt in Vista and type Bcdedit /?. This provides a top-tier list of switches to be used with BCDedit. After you have reviewed the output, type Bcdedit /? Topics. This command displays an alphabetical listing of the switches.

Alert

You should know the following BCDedit switches:

Bcdedit /export <filename>— Backs up the BCD data to a file

Bcdedit /import <filename>— Restores the BCD data from a file

Bcdedit /copy— Copies boot entries from the store

Bcdedit /create— Adds boot entries to the store

Bcdedit /delete— Removes boot entries from the store

Bcdedit /default— Sets the default OS in the Startup menu

Bcdedit /timeout <secs>— Sets the time-out timer value

Bcdedit /debug— Enables the kernel debugger

You should also know the comparable tool used in XP and earlier operating systems:

Bootcfg.exe— Enables you to edit the Boot.ini file

Bootcfg is not used on Windows Vista boot data.


Boot from Installation Media

If LKGC, Safe Mode, and BCDedit aren’t the correct solutions for a failed bootup, you may perform repairs by booting up the computer on the installation media. The Windows Vista installation DVD is bootable. Insert the source DVD for Windows Vista in the DVD drive and reboot the computer. You should be prompted with the following message:

Press any key to boot from CD or DVD . . . .

Note

A Word About Booting and BIOS The hardware must support booting from the CD/DVD drive. In addition, the BIOS of the computer must be configured to boot from CD/DVD before booting from the hard drive.


Strike a key to boot up using the installation media. Doing this boots the system from only files found on the installation media, with no third-party drivers, applications, or modified or corrupted files or configuration parameters from your hard drive. As the computer boots on the installation media, you are prompted for confirmation of the language, time, currency format, and keyboard format. Confirm these by clicking the Next button.

In the next screen, you have the options Install Now (for a new installation of Windows Vista), What to Know Before Installing Windows, or Repair Your Computer, as shown in Figure 2.

Figure 2. Booting the computer from Vista installation media.

Select the Repair Your Computer option. When you select this option, the system searches all drives to identify all instances of operating systems. You are then presented with a dialog box to select which instance of the OS to repair. If you must provide additional drivers (called non-HCL drivers, meaning that the drivers are not on the Microsoft Hardware Compatibility List) to mount drives that contain the OS, you can select to load those additional mass storage device drivers by using the Load Drivers button. This dialog box is shown in Figure 3.

Figure 3. Selecting the OS to repair.


Select Next. This opens the System Recovery Options dialog box that has a worthy collection of recovery options for you (see Figure 4).

Figure 4. System Recovery Options.


To resolve startup problems, click Startup Repair.  You might be prompted to make choices, and your computer may be restarted as Startup Repair tries to fix problems.

Startup Repair scans your computer for these files and tries to repair missing or corrupted boot and system files that prevent Windows Vista from starting correctly.

Note

No More Recovery Console The Repair Your Computer option from the installation media replaces the earlier Recovery Console used on Windows 2000, 2003, and XP. Recovery Console does not exist in Windows Vista.

Other -----------------
- Maintain Desktop Applications (part 2) - Using Group Policy to Manage Application Compatibility
- Maintain Desktop Applications (part 1) - New Program Compatibility Wizard
- Supporting Desktop Applications : Troubleshoot Software Restrictions
- Support Deployed Applications
- Configure Network Security (part 2 ) - Windows Firewall
- Configure Network Security (part1 ) - Secure Files and Printer Shares with Access Control Lists (ACLs)
- Configure and Troubleshoot Remote Access (part 2) - Troubleshooting Windows Vista Remote Access Connections
- Configure and Troubleshoot Remote Access (part 1) - Remote Client Access Connections
- Configure and Troubleshoot Wireless Networking (part 3) - Troubleshooting Wireless Connections
- Configure and Troubleshoot Wireless Networking (part 2) - Wireless Security
 
 
Top 10
- Microsoft Visio 2013 : Adding Structure to Your Diagrams - Finding containers and lists in Visio (part 2) - Wireframes,Legends
- Microsoft Visio 2013 : Adding Structure to Your Diagrams - Finding containers and lists in Visio (part 1) - Swimlanes
- Microsoft Visio 2013 : Adding Structure to Your Diagrams - Formatting and sizing lists
- Microsoft Visio 2013 : Adding Structure to Your Diagrams - Adding shapes to lists
- Microsoft Visio 2013 : Adding Structure to Your Diagrams - Sizing containers
- Microsoft Access 2010 : Control Properties and Why to Use Them (part 3) - The Other Properties of a Control
- Microsoft Access 2010 : Control Properties and Why to Use Them (part 2) - The Data Properties of a Control
- Microsoft Access 2010 : Control Properties and Why to Use Them (part 1) - The Format Properties of a Control
- Microsoft Access 2010 : Form Properties and Why Should You Use Them - Working with the Properties Window
- Microsoft Visio 2013 : Using the Organization Chart Wizard with new data
Popular tags
Microsoft Access Microsoft Excel Microsoft OneNote Microsoft PowerPoint Microsoft Project Microsoft Visio Microsoft Word Active Directory Biztalk Exchange Server Microsoft LynC Server Microsoft Dynamic Sharepoint Sql Server Windows Server 2008 Windows Server 2012 Windows 7 Windows 8 windows Phone 7 windows Phone 8
programming4us programming4us
Celebrity Style, Fashion Trends, Beauty and Makeup Tips.
 
programming4us
Windows Vista
programming4us
Windows 7
programming4us
Windows Azure
programming4us
Windows Server