Disabling the Close Box for an application

I currently use an application called WinTopMost, which prevents users from clicking the "X" to close dos windows. These windows pop up when we run posting procedures. so this prevents a user from aborting a posting before it finishes. Because the software is for non-profits, I'm always looking for a lower cost alternative to what we currently use, which may prove too costly for our customers.

Is there a freeware or group policy that will do the same thing for users who RDP to a Windows2003 R2 server?

Please advise if you need me to supply more information to answer the question.

By the way, that is the absolute best usage agreement I've ever read - simple, to the point, sensible. Loved it.

If there's a better place to have posted this, please advise!