If you attempt to sysprep a machine for acquisition of an Image and the machine crashes during the sysprep process it is likely that the image has been sysprepped more than 3 times.

Symptoms of this issue

run sysprep.exe with /generalize /oobe switches and the process is running for few seconds when then the sysprep window disappears. Opening the sysprep log file under \sysprep\Panther the logfile contains this line:

Date Time, Error [0x0f0073] SYSPRPRunExternalDlls:Not running DLLs; either the machine is in an invalid state orwe couldn’t update the recorded state, dwRet = 31

This error indicates that the image has been syspreped more than 3 times

First check if you can re-arm by running:

slmgr.vbs /dlv

and check the re-arm counter. if it set to zero you need to do the following: http://support.microsoft.com/kb/929828 (set the <SkipRearm>1</SkipRearm> like in the example, note: this option will make the product key window to appear in the setup process).
You can also try running : slmgr.vbs -rearm, to rearm Windows.

Reset the sysprep count to zero

1 – Change few keys in the registry:

HKEY_LOCAL_MACHINE\SYSTEM\Setup\Status\SysprepStatus\GeneralizationState\CleanupState:2

HKEY_LOCAL_MACHINE\SYSTEM\Setup\Status\SysprepStatus\GeneralizationState\GeneralizationState:7

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform\SkipRearm:1

2 – Reset MSDTC

Start -> Run : msdtc -uninstall (wait few seconds)

Start -> Run : msdtc -install (wait few seconds)

3 – Restart the machine
4 – You can now run:

sysprep.exe /generalize /oobe