I assume that you meant "won't", and not "want" (hehe).

Although that wasn't what I was after, it gave me an
idea -- use Application.OnKey

The brute force method would be something along the lines
of...

Application.OnKey "a", ""
Application.OnKey "b", ""
Application.OnKey "c", ""
Application.OnKey "d", ""
.. etc.

This disables each of the keys "a" to "d", one at a time
(note, it is case sensitive, so "A" is still live)

A more elegant way would be:

For ii = 33 to 128
-- Application.OnKey Chr(ii), ""
Next ii

The above will disable any printable character. You could
possibly expand the scope of the loop to handle others.
However, navigation keys and such have specific references
(check out "onkey" on VBA help), although I doubt that they
are giving a6 any problems.

It seems that this loop can go in any sub that gets executed
before the timer  sub begins.