How to prevent users closing a program

I put a scancode in the registry that prevented the windows,ctl,and alt keys from working so noone could break out of a program. This worked OK until we decided to put it onto VPN. Unbeknown to me the VPN required a ctl-alt-del to start the computer so we ended up with a deadlock that was unfixable and had to have the computer sent to the shop.
The VPN installer says I have to find some other way to prevent breaking out of the program but I can't find any other solution.

(edit note - the forum Posting Rules call for a meaningful subject. I changed this one for you since you are fairly new to the forum - Newt)

 

XP pro or home version?

Just one program you don't want users to be able to crash out of?

 

Right - Just the one program

 

XP Pro

 

Didn't find what I was looking for (thought there was an option under gpedit.msc that would block CAD for certain things) but if they are doing CAD to bring up the task manager and killing the app from there, you could set security on taskmgr.exe so users couldn't run it.

 

OK thanks for the effort - and thanks for giving it a sensible title