Change a Windows XP computer name when the computer cannot boot

Last week I came across a weird issue with a few Windows XP Pro computers that were part of an Active Directory domain. In some cases, most likely after playing with the computer’s registry, you might find that a computer running Windows XP Professional has problems in logging on. You enter your username and password, the system looks like it is processing the logon request, but it takes forever and you can never actually get into your desktop.

Naturally, you try to shut down the computer, turn it on again and try to log on, but fail over and over with no apparent error message. The logon process just hangs there. You try to log on locally, but again you fail. You try safe mode, and that too does not help. You even disconnect the network cable (if you have one…), you disconnect all other peripheral devices but it is still stuck! Your computer looks like it is “thinking”, trying to complete the logon process, but it can’t.
The reason for this strange issue is most likely due to some changes in the computer’s registry, causing it to miss some important registry settings, key and values. I’m not saying that this is the cause for the error in a 100% of the times, there *could* be other bugs or causes for this issue.
Anyway, so, how do you edit the local registry without being able to logon to the computer?
It’s time to boot up the machine with a software called “ERD Commander”.
Note: ERD Commander by Wininternals (now owned by Microsoft) is a bootable CD that enables you to boot you computer to a temporary operating system which exist on the CD without installing anything on your computer. After the computer has booted you can access your system’s hard drive, registry and other setting so you can diagnose and repair problems using tools located on the ERD Commander Start menu.
Note: ERD Commander can no longer be obtained from Wininternals, and only Software Assurance customers can get the extended tool – now called “Microsoft Desktop Optimization Pack”. However, if you look well enough on Google you *might* find alternate download links…
The first step is to place the “ERD Commander” CD in the CDROM drive and boot the computer from the CD. The boot process will take some time and you will be logged on (no password is required). After you log on, the desktop looks different from the regular desktop you are used to, and most of the options are limited.
In the Start Menu choose “System” and you will get the following screen:
change cmp name 1 small
Check the “Full computer name” field: if instead of the computer name (“xplap” for example) you see only a dot , you found your problem!!!
In this case, somehow the computer has lost its name, and that is the reason why you couldn’t log on.
The next step is to define a computer name for the computer through the Registry (because ERD commander doesn’t allow defining it in an easier way).
In the Start Menu choose “Regedit”.
Note: As always, be very careful while the editing the Registry. A small mistake can cause huge damage that will prevent you from booting the computer. If you don’t know what the Registry is, how to edit it and how to back it up, please consult with a skilled IT professional.
The Registry editor will open:
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Start browsing the registry for the following paths:

HKEY_LOCAL_MACHINE\SYSTEM\ Key

ControlSet001\Control\ComputerName\ActiveComputerName

ComputerName

ControlSet001\Control\ComputerName\ComputerName

ComputerName

ControlSet001\Services\Eventlog

ComputerName

ControlSet001\Services\Tcpip\Parameters
Hostname

ControlSet001\Services\Tcpip\Parameters
NV
Hostname
 
ControlSet002\Control\ComputerName\ComputerName

ComputerName

ControlSet002\Services\Eventlog

ComputerName

ControlSet002\Services\Tcpip\Parameters

Hostname

ControlSet002\Services\Tcpip\Parameters

NV
Hostname
CurrentControlSet\Control\ComputerName\ActiveComputerName
ComputerName
CurrentControlSet\Control\ComputerName\ComputerName  
ComputerName
CurrentControlSet\Services\Eventlog
ComputerName
CurrentControlSet\Services\Tcpip\Parameters
Hostname
CurrentControlSet\Services\Tcpip\Parameters
NV Hostname

If the problem that caused your computer not to be able to perform the logon process is related to the missing computer name, in every single one of the paths above you will have to create a new key with the EXACT name as listed in the “Key Name” column above.


Note: I suggest you copy and paste the key names, that will prevent silly spelling mistakes and typos.
Right click in the right hand side of the Registry editor screen > New > String value.
change cmp name 3 small
As suggested above, copy the “key name” from the table above and use it for the string name. Double click on the new key and a small window will open, where you will enter the name of your computer. For example:
change cmp name 4 small
Follow the above example to create the whole list of keys that are listed above.
After you finish, logoff ERD Commander and restart your computer normally.
If all went well, it will boot now without any problem and with a new computer name, and you will be able to complete the logon process.
Note: If the computer was (or should be) a part of a domain you might need to re-join it to the domain just like any regular computer. Read my “Join Windows XP to an Active Directory domain” article.

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