After the xp logo screen the screen goes to blank and it just hangs.

This looks like a graphics card fault but changing card does nothing.

Booting into safe mode and it stops at agp driver.

Repairing windows gives a lsass.exe error which cannot be resolved.

Scanning hard drive reveals no viruses.

So far we have had to reformat and reload xp - but I just got another computer with same fault symptoms. I'm wondering if anyone has similar findings and have they discovered cause/fix.

There is a small possibility that an av update may have been cause, but no way to confirm this.

The culprit is the installation of a Windows Service Pack. If the installation of a Windows Service Pack was interrupted for any reason, then you will get these Windows XP hangs during bootup (usually 1 out of 10 tries).

If you can, use System Restore to roll-back to a date prior to the installation of the Service Pack being installed. Once rolled back has completed successfully, then reinstall Service Pack -- this time wait until the Service Pack states it has finished.

Updating the video drivers will not work and you will be wasting your time trying to find another fix

To determine which service pack is currently installed on your computer, follow these steps:

1. Click Start, and then click Run.
   
2. Copy and paste, or type the following command and then click OK:
   
   winver
   (A dialog box displays the version of Windows and the service pack that is currently installed on your computer)

   
   

Here is an article on how to uninstall service pack 3

Method 1: Use the "Add or Remove Programs" item in Control Panel

1. Click Start, and then click Run.
   
2. Copy and then paste the following command in the Open box, and then press ENTER:
   
3. appwiz.cpl
   
4. Click to select the Show Updates check box.
   
5. Click Windows XP Service Pack 3, and then click Remove.
   
6. Click Finish to restart the computer after the removal process is complete.
   

Method 2: Use the hidden $NtServicePackUninstall$ folder

1. Click Start, click Run, type c:\windows\$NtServicePackUninstall$\spuninst\spuninst.exe in the Open box, and then click OK.
   
2. When the Windows XP Service Pack 3 Removal Wizard starts, click Next.
   
3. Follow the instructions on the screen to remove Windows XP SP3.
   

Method 3: Use the System Restore process

Note Before you use System Restore, make sure that you have restarted the computer at least one time after you installed Windows XP SP3. By restarting the computer, you allow for any remaining servicing processes to finish.

1. Click Start, and then click Run.
   
2. Copy and then paste the following command in the Open box, and then press ENTER:
   
3. %systemroot%\System32\restore\rstrui.exe
   
4. Click Restore my computer to an earlier time, and then click Next.
   
5. Click the date on which you installed Windows XP SP3, and then click Installed Window XP Service Pack 3 in the Restore Point box.
   
6. Click Next, and then follow the instructions on the screen to remove Windows XP SP3.
   

Here is an article on how to obtain the latest service pack for xp

You can check the installation log located in WINDOWS to see if SP3 installed properly or there were any serious error during it's installation.

You can also run sfc /scannow

The SfcScan value in the following registry key has three possible settings:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon

The settings for the SfcScan value are:

• 0x0 = do not scan protected files after restart. (Default value)
• 0x1 = scan all protected files after every restart (set if sfc /scanboot is run).
  
  
• 0x2 = scan all protected files one time after a restart (set if sfc /scanonce is run)
  
  

Note: you will more then likely be prompted for your Windows Installation CD unless you copied the i386 directory to your hard drive and updated the registry key

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup

SourcePath = C:\

You may also want to try from the Windows Recovery Console

CHKDSK /P

OR

CHKDSK /R

ALSO TRY and Boot into Safe Mode to see if you can get past the blank screen

Access safe mode by pressing the F8 key just before Windows XP begins to boot (you may have to press F8 repeatedly). Upon doing so, the Windows boot menu will be displayed, which gives you several different boot modes to choose from. Below is a brief explanation of each of these modes:

• Safe Mode -- Safe Mode boots Windows using a minimal driver set and without loading any startup applications.
  
• Safe Mode with Networking -- This option does the same thing as Safe Mode, except that it also loads the drivers and services necessary for network access.
  
  
• Safe Mode with Command Prompt -- This option is similar to Safe Mode, except that the system boots to a command prompt rather than to a GUI. This option is most useful for repairing GUI-related problems.
  
  
• Enable Boot Logging -- If you select this option, Windows will create a diagnostic log of the boot process. You can use this log to figure out where the process is breaking down. The log file is named NTBLOG.TXT and is located in the %SYSTEMROOT% folder. You can use boot logging in conjunction with any of the safe mode boot options except for the Last Known Good Configuration option.
  
  
• Enable VGA Mode -- The Enable VGA Mode option is intended for use when the correct video driver is installed, but Windows was accidentally configured to use an incompatible display resolution. The Enable VGA Mode option boots Windows using the current video driver but uses a 640 x 480 resolution. This gives you the opportunity to reset the display resolution. Safe Mode and Safe Mode with Networking also use a decreased screen resolution but do so by using the VGA.SYS driver rather than the video driver that was specifically designed for your video card. Therefore, the Enable VGA Mode is the option of choice for resetting the display resolution.
  
  
• Last Known Good Configuration -- When Windows boots successfully, it makes note that it was able to boot successfully by marking the configuration as "good." If you make a configuration change that renders Windows unbootable, you can select the Last Known Good Configuration option to boot Windows using a known good configuration.
  
  
• Directory Services Restore Mode -- Although this option appears on Windows XP's menu, it is only valid for Windows Server machines that are acting as domain controllers.
  
  
• Debugging Mode -- This option is an obsolete leftover from Windows NT. The option allows you to send debugging information over a serial port (COM2) to another computer that is running a debugger. However, modern computers are no longer equipped with traditional serial ports.
  
  
• Disable Automatic Restart on System Failures -- This option prevents Windows from automatically rebooting when a blue screen error occurs. It is useful for troubleshooting when a machine mysteriously reboots itself in the middle of the night.
  
  
• Start Windows Normally -- This option causes Windows to load in the normal way.
  
  
• Reboot -- Use this option to reboot the machine.
  
  
• Return to OS Choice Menu -- Selecting this option takes you to a screen that lets you choose which of the installed operating systems you want to boot. Unless you are running a dual boot or a multi-boot configuration, Windows XP will be the only choice.
  

Once logged in via safe mode, check these registry keys to see what is being started during bootup

Windows differentiates between processes that are only run during the next reboot and those that are configured to run every time Windows is started. Calls to processes that are run only after the next reboot can be found beneath the following registry locations:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce

HKEY_Current_User\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce

Finding calls to processes that run each time Windows is booted is a bit trickier. Here are the primary locations where these calls are stored:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

HKEY_Current_User\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

SOMETHING ELSE TO TRY

Insert Hiren BootCD 10.1 with Windows XP running and try the following tools to show which programs are launching during startup

1. Autoruns 9.56
   
   
   Displays All the entries from startup folder, Run, RunOnce, and other Registry keys, Explorer shell extensions,toolbars, browser helper objects, Winlogon notifications, auto-start services, Scheduled Tasks, Winsock, LSA Providers, Remove Drivers and much more which helps to remove nasty spyware/adware and viruses.
   
2. Silent Runners Revision 60
   
   
   A free script that helps detect spyware, malware and adware in the startup process
   
   
3. Startup Control Panel 2.8
   
   
   a tool to edit startup programs
   
   
4. Startup Monitor 1.02
   
   
   it notifies you when any program registers itself to run at system startup
   
   
5. HijackThis 2.0.2
   
   
   a general homepage hijackers detector and remover and more
   

Very strange but unplugging the external drive seems to work. The external drive is USB and is only used for backup by the Backup Software called Cobian? Ever hear of this?

It sounds like the backup software may have made a copy of the entire drive to include the Master Boot Record and if the PC's BIOS has USB as a bootable device before the hard-drive then this could possibly be an issue.

Which makes we wonder, is the Windows XP splash screen from the PC running off the external drive and of course it can't go any further?

I believe what needs to happen is, verify/examine the external drive and also make sure the DELL BIOS doesn't have USB as a bootable device before the internal hard drive.

This issue I am troubleshooting doesn't appear to be the external drive as it was unplugged and the system was still hanging at the blank screen after forcing a shutdown (by holding the power button down) four seperate times before the PC came up.

Monday I am going to go onsite and do:

winver (note version of xp... Home or Professional and current Service Pack)

sfc /scannow (will take approx 30 minutes which will check to see if all necessary files are present. NOTE: may prompt for XP CD)

insert Hiren BootCD v10.1 and run the following programs looking for what is starting up with Windows

Autoruns 9.56, Silent Runners Revision 60, Startup Control Panel 2.8, and HijackThis 2.0.2

Instead of today (Monday) I went in on Friday and did the whole sfc /scannow which took about a full 30 minutes an prompted for the XP Professional CD a lot but didn't appear to resolve anything. When finished, the progress bar just goes away.

Also checked for startup registry entries and programs, looking for something unusual or that may be causing an issue and found nothing.

Installed pagedefrag and smartdefrag to keep the system free of fragments seeing how when the system goes to a black/blank screen during bootup, the only option is to hold the power button in until it shuts down and then start it back up again. This causes some serious fragments on the drive.

It could be a bad block on the drive which a chkdsk would discover.

It could also be bad software... I am just starting to think it could be Powerchute software since no APC is plugged in, it may be looking for the backup unit during bootup. The best approach is to remove any not required software from the system and see if that resolves the issue.

Per the second post in this thread it mentions service pack 3 could be corrupt but I thought the sfc /scannow would of resolved that issue (maybe not). So I could also try and uninstall and reinstall of service pack 3.