Using Edit v 0.5 (the one distributed with Beta 8 of FreeDOS).  

If one hits Ctrl-C while running EDIT, the program terminates and one is given 
a C:> prompt.  However, the termination is not clean.  Something is corrupted 
in memory and the system will crash if one tries to run another program, such 
as edit, zip, emacs, gem, etc.  During the crash, the hard disk access light 
comes on and stays on.  Only a hard reset will reboot the computer.   

Rather than troubleshoot the problem, I'd suggest that Ctrl-C simply get 
trapped by the program and ignored.  So many editors nowadays use the Windows 
key sequence of Ctrl-C for copy that it is easy for a user to hit it by habit, 
losing his/her work.  

Test platform was Pentium 150, 32 MB RAM, FreeDOS beta 8, using FXDMS (<64 MB 
version) memory manager.  

This bug was fixed in version 0.6

Joe

EDIT 0.6 used to hook the timer and keyboard IRQ handlers.

My EDIT 0.7 implementation now works without those handlers,
so even if you manage to crash it, nothing is left behind
dangling in unallocated RAM. Further, Ctrl-C is used for
"copy to clipboard" and has the "abort" meaning of DOS
blocked as you suggested.