Windows 3.11, 95 keyboard buffer?

Is there a keyboard buffer for windows 3.11 and 95? I have a program that sets
an ISR to prevent CTRL-ALT-DEL, but it only works under DOS, this is for a
program that is supposed to prevent access to the computer while you are away.
It works fine under DOS, but DOS under windows(not dos box) brings up that
program manager and that circumvents my security program! Is there any way to
prevent this under TP6?
Please CC to my e-mail as my ISP's server is very unreliable. Thanks