DANGEROUS TECHNIQUE DESCRIBED BELOW. THIS WILL MODIFY YOUR DESKTOP OR LAPTOP COMPUTER TO THE EXTENT THAT IT WILL BE EXTREMELY DIFFICULT IF NOT IMPOSSIBLE TO RECOVER CONTROL OF THE SYSTEM. MAKE an image and put it on a bootable CD or DVD if you insist on playing with this on a computer you need to keep running.
My previous comments about Control-Alt-Delete not working still apply. Control C and Control-Break don't do much either.
In HKLM\Software\Windows NT\CurrentVersion\WinLogon\Shell
replace Explorer.exe with the BATCH file as described in Not-so-Stupid Nerd Trick, a previous blog. The second step is to NOT modify the setting in IniFileMapping. Third step is to have the system Auto-Logon as described previously. On the next reboot, the fun begins. Done.
With the system set this way, it becomes a single-purpose computer, an appliance as it were. It will not run any User programs other than what you've programmed into the batch file.
With this registry entry you've basically shackled the computer to a single task and that is exactly perfect for kiosks, public information displays, embedded systems tasks etc. It doesn't matter what the User settings are, the system never bothers to execute the the User programmed shell.
An interesting experiment would be to set the System Shell to be FireFox or Chrome. Consider it a taste of things to come, if you believe the Cloud enthusiasts.
You could set the "XP appliance" system up to be a printer server for other computers in the office. Just set the printer management software to be the application started by the batch file. Make sure the Auto-Logon user has printer management permissions.
The old XP computer becomes your dedicated printer management tool. Make sure to share the printer(s) out to all other users. This could be a way to use an old XP Pro license on a slow system that can't run Visaster or Win7. Dumping the printer tasks to an XP Printer will speed up the rest of the desktops when printing. This should be possible with any sort of printer. Or multiple printers connected to the XP Pro box.
BTW if you set up another account as admin that has remote logon capabilities, you can use one of the VNC tools to "manage" the system remotely or to break into the registry and hack the shell back to Explorer.exe. Remember to spell out the file extension, Explorer.EXE.