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Booting Hangs at a Black Screen with a Blinking White Underscore Cursor

The following is a procedure for repairing a system using the Microsoft utility called the  Recovery Console. This will not affect any of your files or programs on your PC, but will allow you to restore the PC's booting functionality if "Booting Hangs at a Black Screen with a Blinking White Underscore Cursor" and your system is still functional otherwise.

Ways to Run the Recovery Console

Running the Recovery Console can be done several ways:

• Booting from an XP Installation CD and then choosing the option to run the Recovery Console rather than actually installing or reinstalling XP. The vast majority of store-bought PC owners are not supplied with an XP Installation CD.
  
  
• Booting from a Recovery Console CD.
  
  
• Booting into the Recovery Console as a dual-boot option after it has been installed onto the hard drive using an XP Installation CD.

If you have a Windows XP Installation CD   (not a Restore CD or Recovery CD):

Insert your Windows XP Installation CD into the hoarked PC's primary optical drive and reboot the PC.

If you DO NOT have a Windows XP Installation CD:

1. Download the file RC-n.iso (Recovery Console CD image file) from Here.
   http://www.thecomputerparamedic.com/files/rc.iso
   
2. Burn this ISO CD image to a blank CD-R.
   
   NOTE:   Keep in mind that burning an ISO image file to a blank CD-R is different than burning an ordinary data file.  If you do not know how to burn an ISO image, then download CDBurnerXP Pro to another Windows machine and install it.
   http://www.thecomputerparamedic.com/files/rc.iso

Starting the Recover Console (from either kind of CD)

Make sure the hoarked PC's BIOS is configured to try to boot from the optical drive before it tries to boot from the hard disk drive.

NOTE:  You do this by starting the BIOS configuration program by pressing a key such as F1, F2, Esc or the Delete/Del key just after the BIOS finished it's POST (Power-Up Self Test),  but before Windows announces it is starting to load.)

Press any key to boot from the CD.  After the first several screens display, you will be given a choice to choose R to run the Recovery Console rather than performing (or trying to perform) an XP installation or reinstallation.  You will be asked to log in.

NOTE: For Windows XP Home, there is no password necessary, just press Enter.  For Windows XP Pro, MCE and 64-bit, ask whomever set up the machine what password they used and then enter that.

When you see the Recovery Console's command-line prompt,   >  , then continue to the section Recovery Console Commands to Enter.

If you get an access denied error when doing the above, then enter the following at the Recovery Console prompt:

cd  \windows\system32\config  {Enter}

ren  system  system.bak  {Enter}

exit  {Enter}

Your PC will reboot,  restart the Recovery Console and start the instructions from the beginning of this section.

If you still cannot get access to your installation in the Recovery Console then your SAM Registry file is corrupt.  There is no way you can restore this with the Recovery Console.  You may need to do a fresh XP install, Repair Install, a Recovery or a Restore.

Recovery Console Commands to Enter

1) CHKDSK corrects any file system problems.

Syntax:   chkdsk  [device] [/p]  [/r]

Example:  chkdsk  \Device\Harddisk0\Partition1  /r

Device is an option parameter that specifies which partition/volume on which hard drive should be checked. All the drives and their partitions can be listed by issuing the map command.  The XP OS partition is usually designated as \Device\Harddisk0\Partition1

> chkdsk  /r  {Enter}

This will make sure the file system is working properly. However, if any files are corrupted, they will remain corrupted.  This will also try to recover the contents of any corrupted files, but this may not succeed in any/some cases.

2) FIXMBR rewrites the Master Boot Record (MBR) on the hard drive.

Syntax:   fixmbr  [device_name]

Example:  fixmbr  \Device\Harddisk0

Note that device_name omits any partition notation since all hard drives can have only one MBR no matter how many partitions it has been divided into.

> fixmbr  {Enter}

3)  FIXBOOT write a new Boot Sector to a partition/volume on the hard drive. The Boot Sector contains the Boot Loader program which loads the operating system.

Syntax:   fixboot  [drive]

Example:  fixboot  c:

Note that drive is a partition/volume letter. The map command also lists partition/volume letters.

> fixboot  c:  {Enter}

At this point you are ready to exit the Recovery Console and restart your PC to see if, once again, you are able to boot to your account's Desktop.

> exit  {Enter}

Other Things you Should Know

So, you have started or restarted your PC and get the "Blank screen with a blinking underscore cursor".

This is what you can tell so far:

• The CPU is OK – otherwise you'd have a dead PC.  There is no such thing as a "marginally functional" CPU – it either works right or it doesn't work at all.
  
• The RAM is probably OK.  However, it may be faulty, but this is easy to check and replace if necessary.
  
• The motherboard is probably OK – otherwise you'd have a dead PC.
  
• The Power Supply Unit (PSU) in a desktop PC or the power regulation circuitry in a laptop are probably OK – or you'd have a dead PC or one that randomly reboots or bluescreens (the feared BSOD - Blue Screen Of Death).  If it is a laptop then the battery is functional.
  
• The BIOS (Basic I/O System) is OK because it has done its POST (Power-On Self Test) and has detected the keyboard, mouse, memory, RAM and video adapter.  You know this because is has not complained about not finding any of these.
  
• The Video Adapter (a chip on a laptop's motherboard, a chip or plug-in card in a desktop PC) has been found by the BIOS, has been initialized by the BIOS and is working properly – at least in text mode. That blinking cursor has been created by the BIOS program and being generated by the video adapter.  Oh yeah, the monitor is working, too, displaying that cursor.
  
• The BIOS has located a hard drive – it hasn't complained that it could not find one.

This is all very good. It means that the BIOS and the majority of the hardware components are working properly.

So, what's left that could be wrong ?  The Hard Disk Dive (HDD)

• The operation of the hard drive's electronics and mechanics;
  
• The files that are supposed to be on the drive.

Hard drive electronics and the mechanical operation can be directly checked with a diagnostic program:

Run drive test utility from your drive’s manufacturer to make sure the drive is functionally OK.  Use the diagnostic associated with the brand drive you have:

• Seagate/Maxtor/Quantum           http://www.seagate.com/www/en-us/support/downloads/
• Western Digital            http://support.wdc.com/download/
• Hitachi/IBM              http://www.hitachigst.com/hdd/support/download.htm
• Samsung               http://www.samsung.com/in/products/harddiskdrives/utilities/hutil.htm
• Fujitsu              http://www.fujitsu.com/us/services/computing/storage/hdd/support/utilities.html

More Information

There's lots more information out there about the Recovery Console and all its available commands. Some commands work similarly to the ones in XP's command window – but watch out because they may have different options and work differently to their counterparts. Here are the official MS web pages describing the 3 commands listed above used in the Recovery Console:

The Recovery Console

Recovery Console Commands

Recovery_Console_Command_Reference.htm

Description of the Windows XP Recovery Console    

http://support.microsoft.com/kb/314058

A discussion about the Bootcfg command and its uses - MS KB 291980   http://support.microsoft.com/kb/291980